<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:02b58962-0445-417c-9402-17ace769e9bb,g:041144b9-0454-4b11-9601-c388d366deca-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CoverPage" xlink:type="simple" xlink:href="bkh-20210331.xsd#CoverPage"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CoverPage" xlink:type="extended" id="i85d5f07605e046a39d0de6112f6f728c_CoverPage"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofIncomeunaudited" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedStatementsofIncomeunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofIncomeunaudited" xlink:type="extended" id="if537c75777024c5d8d4ff714ff99b090_CondensedConsolidatedStatementsofIncomeunaudited"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunaudited" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedStatementsofComprehensiveIncomeunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunaudited" xlink:type="extended" id="i8bb4a64490384da4a64497fbee944cc5_CondensedConsolidatedStatementsofComprehensiveIncomeunaudited">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_4a56dfb0-05d4-447e-a307-cf6966e5d5bd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_094913e8-bb27-40c7-805b-53c51be4354d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4a56dfb0-05d4-447e-a307-cf6966e5d5bd" xlink:to="loc_us-gaap_ProfitLoss_094913e8-bb27-40c7-805b-53c51be4354d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_4a56dfb0-05d4-447e-a307-cf6966e5d5bd" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_712214b1-e168-4877-845a-087109c5f5b8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax_712214b1-e168-4877-845a-087109c5f5b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax_4cd2d9e5-fcfd-4186-81c8-4774f18b2154" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax_4cd2d9e5-fcfd-4186-81c8-4774f18b2154" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_50dfdfb1-9b7e-442e-b92a-29b98d96ac4c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax_50dfdfb1-9b7e-442e-b92a-29b98d96ac4c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax_d47d9008-aa58-4631-a933-90a1866b48d0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax_d47d9008-aa58-4631-a933-90a1866b48d0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_71cff7eb-f77b-4c7e-9520-27ac295c872e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_71cff7eb-f77b-4c7e-9520-27ac295c872e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_09bf88fe-3dfb-40dc-88ae-cf68b658688b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_09bf88fe-3dfb-40dc-88ae-cf68b658688b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_cc2558d5-35d1-40f7-9238-1cacc859c5cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_cc2558d5-35d1-40f7-9238-1cacc859c5cc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_b25b69cc-7ea4-4abe-9fc6-a89090257a73" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_b25b69cc-7ea4-4abe-9fc6-a89090257a73" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_1b966d76-01b9-49e7-9404-528f72984d78" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_1aa2519c-9a9f-4726-9b50-7d604ae1e41f" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_1b966d76-01b9-49e7-9404-528f72984d78" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_9aa62057-e00b-4e7b-b520-8f4834757647" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_4a56dfb0-05d4-447e-a307-cf6966e5d5bd" xlink:to="loc_us-gaap_StatementTable_9aa62057-e00b-4e7b-b520-8f4834757647" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_1ce0db28-817a-4fe4-99be-8dba07e3e301" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9aa62057-e00b-4e7b-b520-8f4834757647" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_1ce0db28-817a-4fe4-99be-8dba07e3e301" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1ce0db28-817a-4fe4-99be-8dba07e3e301_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1ce0db28-817a-4fe4-99be-8dba07e3e301" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1ce0db28-817a-4fe4-99be-8dba07e3e301_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_3f936c24-6507-4926-9e05-0da72fab48bb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_1ce0db28-817a-4fe4-99be-8dba07e3e301" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_3f936c24-6507-4926-9e05-0da72fab48bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_bac7a733-5428-4ee6-8e8e-48edba27c749" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_3f936c24-6507-4926-9e05-0da72fab48bb" xlink:to="loc_us-gaap_InterestRateSwapMember_bac7a733-5428-4ee6-8e8e-48edba27c749" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_c0fd84fd-5c13-48c7-9809-ccfb2c808b26" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_3f936c24-6507-4926-9e05-0da72fab48bb" xlink:to="loc_us-gaap_CommodityContractMember_c0fd84fd-5c13-48c7-9809-ccfb2c808b26" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical" xlink:type="extended" id="ib730958c314240b7b40886e9b9332a05_CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_d6baa2e7-7ee6-4625-9127-4eac3023bd4b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_d6baa2e7-7ee6-4625-9127-4eac3023bd4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect_5f3be1d1-cd7c-4c5c-8071-672afd055fcd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect_5f3be1d1-cd7c-4c5c-8071-672afd055fcd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax_587673b2-d527-4493-8c48-a9020996d1ff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax_587673b2-d527-4493-8c48-a9020996d1ff" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax_681a00de-d063-491a-a438-461006780e8b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesTax_681a00de-d063-491a-a438-461006780e8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax_3219964e-8e11-4690-b3e1-483a3a8579c9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodTax_3219964e-8e11-4690-b3e1-483a3a8579c9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_79e7bbfb-14be-43c4-baee-d85841e84ee9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_9b596a9e-d7ad-4cc3-b322-e0624489c4d9" xlink:to="loc_us-gaap_StatementTable_79e7bbfb-14be-43c4-baee-d85841e84ee9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_f57332cd-2504-4daa-b7eb-844978a42d0c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_79e7bbfb-14be-43c4-baee-d85841e84ee9" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_f57332cd-2504-4daa-b7eb-844978a42d0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_f57332cd-2504-4daa-b7eb-844978a42d0c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_f57332cd-2504-4daa-b7eb-844978a42d0c" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_f57332cd-2504-4daa-b7eb-844978a42d0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5375b3b3-40a4-4539-8d21-b4c519a61e04" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_f57332cd-2504-4daa-b7eb-844978a42d0c" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5375b3b3-40a4-4539-8d21-b4c519a61e04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_6b3f144b-3ab8-4870-843d-224b17da802e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5375b3b3-40a4-4539-8d21-b4c519a61e04" xlink:to="loc_us-gaap_InterestRateSwapMember_6b3f144b-3ab8-4870-843d-224b17da802e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_bb3447e0-5c8a-41d0-8a91-953acdf9bca1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5375b3b3-40a4-4539-8d21-b4c519a61e04" xlink:to="loc_us-gaap_CommodityContractMember_bb3447e0-5c8a-41d0-8a91-953acdf9bca1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedBalanceSheetsunaudited" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedBalanceSheetsunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedBalanceSheetsunaudited" xlink:type="extended" id="id0a15deeba93432c8f17d256814bd707_CondensedConsolidatedBalanceSheetsunaudited"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedBalanceSheetsunauditedParenthetical" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedBalanceSheetsunauditedParenthetical"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedBalanceSheetsunauditedParenthetical" xlink:type="extended" id="id760c38bf31b41ee9fba876e4f0b7be4_CondensedConsolidatedBalanceSheetsunauditedParenthetical"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofCashFlowsunaudited" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedStatementsofCashFlowsunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofCashFlowsunaudited" xlink:type="extended" id="ibc836086571c4405b4fc931dac1128ae_CondensedConsolidatedStatementsofCashFlowsunaudited"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofEquityunaudited" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedStatementsofEquityunaudited"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofEquityunaudited" xlink:type="extended" id="i1bd0e45d9af14c609770a14740b0bfad_CondensedConsolidatedStatementsofEquityunaudited">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_cef3a1c1-2f84-48fa-a871-891558bbf5d8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cef3a1c1-2f84-48fa-a871-891558bbf5d8" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_41a5587e-f013-4ac4-b3b0-1d28c2120865" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_41a5587e-f013-4ac4-b3b0-1d28c2120865" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_ad4afef5-49ca-42d3-a723-3f4f89da3a01" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_ad4afef5-49ca-42d3-a723-3f4f89da3a01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_46ce4b76-5c78-45bd-8e43-14514be6e07e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_ProfitLoss_46ce4b76-5c78-45bd-8e43-14514be6e07e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_4a10a8b9-cf0d-4e40-8309-9ef43f56a667" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_4a10a8b9-cf0d-4e40-8309-9ef43f56a667" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_ea850ed8-fb0c-475d-b5f4-d19e5448876f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_DividendsCommonStockCash_ea850ed8-fb0c-475d-b5f4-d19e5448876f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_0ac63b1d-0ad1-4019-b7c7-0073748b2779" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_0ac63b1d-0ad1-4019-b7c7-0073748b2779" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_0289acd3-0d3b-4679-874c-8c2ff9f02b1f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_0289acd3-0d3b-4679-874c-8c2ff9f02b1f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_50f43a32-b72e-4637-8059-ae4af43dfbc9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_StockholdersEquityOther_50f43a32-b72e-4637-8059-ae4af43dfbc9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_1f22a765-5dbd-4011-9891-9ee1e2d8bb75" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_1f22a765-5dbd-4011-9891-9ee1e2d8bb75" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_223734a1-b4b9-425a-bee6-f233d806ae6b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_223734a1-b4b9-425a-bee6-f233d806ae6b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_65986493-7e09-4553-b5b8-b35d6c2dc48d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_65986493-7e09-4553-b5b8-b35d6c2dc48d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_ed461690-4fa3-4b7a-bbe6-bb8fc6c149d1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_c1fd6f4b-065c-4e5b-986b-9c3005e81113" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_ed461690-4fa3-4b7a-bbe6-bb8fc6c149d1" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_e5c56a2a-4b7e-4f35-b37f-0c4f2240af56" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_7715d2b6-0014-433b-b51c-ad818fac97ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a4bffca2-4dce-497a-ba61-6417b6900077" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_cef3a1c1-2f84-48fa-a871-891558bbf5d8" xlink:to="loc_us-gaap_StatementTable_a4bffca2-4dce-497a-ba61-6417b6900077" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_312d905a-c250-4908-b832-cba78ebe0cd5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a4bffca2-4dce-497a-ba61-6417b6900077" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_312d905a-c250-4908-b832-cba78ebe0cd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_312d905a-c250-4908-b832-cba78ebe0cd5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_312d905a-c250-4908-b832-cba78ebe0cd5" xlink:to="loc_us-gaap_EquityComponentDomain_312d905a-c250-4908-b832-cba78ebe0cd5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_312d905a-c250-4908-b832-cba78ebe0cd5" xlink:to="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_ead5517e-ca89-4d79-a414-cf954d60f66a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:to="loc_us-gaap_CommonStockMember_ead5517e-ca89-4d79-a414-cf954d60f66a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_8a8ae4bc-2111-499f-8f5f-d6e2f4b496cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:to="loc_us-gaap_TreasuryStockMember_8a8ae4bc-2111-499f-8f5f-d6e2f4b496cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_485afe6b-dbdf-4e98-a751-fe2837f111e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_485afe6b-dbdf-4e98-a751-fe2837f111e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_bc3c2206-d955-4994-99c4-ed9335a57519" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:to="loc_us-gaap_RetainedEarningsMember_bc3c2206-d955-4994-99c4-ed9335a57519" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_51ae17be-03be-4c39-a9b9-c80ea502ab6b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_51ae17be-03be-4c39-a9b9-c80ea502ab6b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_c548e9bc-a8b8-4abb-94cf-ca60d529c3e8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ba9fc208-bef0-4fab-85e3-30ec719928ad" xlink:to="loc_us-gaap_NoncontrollingInterestMember_c548e9bc-a8b8-4abb-94cf-ca60d529c3e8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_0131d985-8abd-41ef-8ff8-80c7cb597c20" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a4bffca2-4dce-497a-ba61-6417b6900077" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_0131d985-8abd-41ef-8ff8-80c7cb597c20" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_0131d985-8abd-41ef-8ff8-80c7cb597c20_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_0131d985-8abd-41ef-8ff8-80c7cb597c20" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_0131d985-8abd-41ef-8ff8-80c7cb597c20_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_327bd5e9-ef04-45af-a3b6-8a51f5b93ca2" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_0131d985-8abd-41ef-8ff8-80c7cb597c20" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_327bd5e9-ef04-45af-a3b6-8a51f5b93ca2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_6a3324bb-1b15-4278-91b1-5091eecb92ef" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_327bd5e9-ef04-45af-a3b6-8a51f5b93ca2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_6a3324bb-1b15-4278-91b1-5091eecb92ef" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofEquityunauditedParenthetical" xlink:type="simple" xlink:href="bkh-20210331.xsd#CondensedConsolidatedStatementsofEquityunauditedParenthetical"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CondensedConsolidatedStatementsofEquityunauditedParenthetical" xlink:type="extended" id="i208e8135df184454a63c6bd1285a25dd_CondensedConsolidatedStatementsofEquityunauditedParenthetical"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/ManagementsStatement" xlink:type="simple" xlink:href="bkh-20210331.xsd#ManagementsStatement"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/ManagementsStatement" xlink:type="extended" id="i8923ba1bbda44f52880f8afa3453613f_ManagementsStatement"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/ManagementsStatementPolicies" xlink:type="simple" xlink:href="bkh-20210331.xsd#ManagementsStatementPolicies"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/ManagementsStatementPolicies" xlink:type="extended" id="i54ce76d638674cb7a2cc8129b18c50b9_ManagementsStatementPolicies"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMatters" xlink:type="simple" xlink:href="bkh-20210331.xsd#RegulatoryMatters"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMatters" xlink:type="extended" id="ibeb1d121ef25463688f14c9c0b58bf0f_RegulatoryMatters"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#RegulatoryMattersTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersTables" xlink:type="extended" id="i7a4ee6e4b2704944a768993375d2661d_RegulatoryMattersTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RegulatoryMattersDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersDetails" xlink:type="extended" id="i89669a572c834f76ba77abbae0ce5464_RegulatoryMattersDetails">
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c357063e-01a0-4161-bbf8-d830e0d7474d" xlink:href="bkh-20210331.xsd#bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetRegulatoryAssetsAbstract_5801b549-7248-45de-8f05-5ad3c357ba3e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetRegulatoryAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c357063e-01a0-4161-bbf8-d830e0d7474d" xlink:to="loc_us-gaap_NetRegulatoryAssetsAbstract_5801b549-7248-45de-8f05-5ad3c357ba3e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_9edd9c27-b77c-4da4-90bd-1ac9aed64e38" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetRegulatoryAssetsAbstract_5801b549-7248-45de-8f05-5ad3c357ba3e" xlink:to="loc_us-gaap_RegulatoryAssets_9edd9c27-b77c-4da4-90bd-1ac9aed64e38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsCurrent_2f70adf1-1333-46e8-8d4e-be526ae98122" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetRegulatoryAssetsAbstract_5801b549-7248-45de-8f05-5ad3c357ba3e" xlink:to="loc_us-gaap_RegulatoryAssetsCurrent_2f70adf1-1333-46e8-8d4e-be526ae98122" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsNoncurrent_cd9eaec4-3c95-423b-bfa4-3054393f62a6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetRegulatoryAssetsAbstract_5801b549-7248-45de-8f05-5ad3c357ba3e" xlink:to="loc_us-gaap_RegulatoryAssetsNoncurrent_cd9eaec4-3c95-423b-bfa4-3054393f62a6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_a1dbf1fa-6cf8-4ddb-b6f2-08bb3c4c4d68" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c357063e-01a0-4161-bbf8-d830e0d7474d" xlink:to="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_a1dbf1fa-6cf8-4ddb-b6f2-08bb3c4c4d68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilities_74f61da7-610d-495d-815e-0081e0ee8e41" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_a1dbf1fa-6cf8-4ddb-b6f2-08bb3c4c4d68" xlink:to="loc_us-gaap_RegulatoryLiabilities_74f61da7-610d-495d-815e-0081e0ee8e41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityCurrent_e2d04656-5f84-46e1-9c62-21850ca7e217" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_a1dbf1fa-6cf8-4ddb-b6f2-08bb3c4c4d68" xlink:to="loc_us-gaap_RegulatoryLiabilityCurrent_e2d04656-5f84-46e1-9c62-21850ca7e217" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityNoncurrent_e2ca5108-76e0-40f3-91eb-81715fab55c7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetsAndLiabilitiesOtherDisclosuresAbstract_a1dbf1fa-6cf8-4ddb-b6f2-08bb3c4c4d68" xlink:to="loc_us-gaap_RegulatoryLiabilityNoncurrent_e2ca5108-76e0-40f3-91eb-81715fab55c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_cc516685-9ec3-4af1-a3f4-4eb37a14cef9" xlink:href="bkh-20210331.xsd#bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesLineItems_c357063e-01a0-4161-bbf8-d830e0d7474d" xlink:to="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_cc516685-9ec3-4af1-a3f4-4eb37a14cef9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_40dd68a1-b84a-4c07-91c4-615bb4aa7754" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_cc516685-9ec3-4af1-a3f4-4eb37a14cef9" xlink:to="loc_us-gaap_RegulatoryAssetAxis_40dd68a1-b84a-4c07-91c4-615bb4aa7754" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_40dd68a1-b84a-4c07-91c4-615bb4aa7754_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_40dd68a1-b84a-4c07-91c4-615bb4aa7754" xlink:to="loc_us-gaap_RegulatoryAssetDomain_40dd68a1-b84a-4c07-91c4-615bb4aa7754_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_40dd68a1-b84a-4c07-91c4-615bb4aa7754" xlink:to="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFuelCostsMember_adb3ef3a-a055-49a9-805a-cc7fda195792" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFuelCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_DeferredFuelCostsMember_adb3ef3a-a055-49a9-805a-cc7fda195792" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRecoverableGasCostsMember_f29fb761-7c9e-4068-9dc9-e9a1d01ab76a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetRecoverableGasCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_AssetRecoverableGasCostsMember_f29fb761-7c9e-4068-9dc9-e9a1d01ab76a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativeMember_6fcee7af-2ac4-443f-891e-1be7e087c51a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PriceRiskDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_PriceRiskDerivativeMember_6fcee7af-2ac4-443f-891e-1be7e087c51a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AllowanceForFundsUsedDuringConstructionMember_99ae48ec-6a97-4a37-809d-af9794773284" xlink:href="bkh-20210331.xsd#bkh_AllowanceForFundsUsedDuringConstructionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_bkh_AllowanceForFundsUsedDuringConstructionMember_99ae48ec-6a97-4a37-809d-af9794773284" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_83d661cd-9a02-41a0-9e1a-97371b027a31" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_83d661cd-9a02-41a0-9e1a-97371b027a31" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EnvironmentalMember_d041ca60-3013-42d2-b2cc-f274a8bca1bc" xlink:href="bkh-20210331.xsd#bkh_EnvironmentalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_bkh_EnvironmentalMember_d041ca60-3013-42d2-b2cc-f274a8bca1bc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossOnReacquiredDebtMember_314a0ef0-cc54-48da-9998-e71fb0b89741" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LossOnReacquiredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_LossOnReacquiredDebtMember_314a0ef0-cc54-48da-9998-e71fb0b89741" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FlowThroughAccountingMember_37d0be38-bb3e-42a8-a4a9-5a2c5cff0871" xlink:href="bkh-20210331.xsd#bkh_FlowThroughAccountingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_bkh_FlowThroughAccountingMember_37d0be38-bb3e-42a8-a4a9-5a2c5cff0871" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnvironmentalRestorationCostsMember_db1dabd5-7724-4251-aef4-56960d68bcc3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EnvironmentalRestorationCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_EnvironmentalRestorationCostsMember_db1dabd5-7724-4251-aef4-56960d68bcc3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasSupplyContractTerminationMember_6734332e-ff06-4164-96ac-eeae6c995a82" xlink:href="bkh-20210331.xsd#bkh_GasSupplyContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_bkh_GasSupplyContractTerminationMember_6734332e-ff06-4164-96ac-eeae6c995a82" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherRegulatoryAssetsMember_ee219a06-22c9-41c1-9537-d467674a8194" xlink:href="bkh-20210331.xsd#bkh_OtherRegulatoryAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_bkh_OtherRegulatoryAssetsMember_ee219a06-22c9-41c1-9537-d467674a8194" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StormCostsMember_465d3a7a-bb4b-4eaa-9f78-a4c5aefbc79b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StormCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_b92e702a-9020-43f7-a534-7be509666caa" xlink:to="loc_us-gaap_StormCostsMember_465d3a7a-bb4b-4eaa-9f78-a4c5aefbc79b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityAxis_ec3cd88b-f634-4b1c-ba97-fc58a09c2cb2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryLiabilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_bkh_ScheduleOfRegulatoryAssetsAndLiabilitiesTable_cc516685-9ec3-4af1-a3f4-4eb37a14cef9" xlink:to="loc_us-gaap_RegulatoryLiabilityAxis_ec3cd88b-f634-4b1c-ba97-fc58a09c2cb2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_ec3cd88b-f634-4b1c-ba97-fc58a09c2cb2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_ec3cd88b-f634-4b1c-ba97-fc58a09c2cb2" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_ec3cd88b-f634-4b1c-ba97-fc58a09c2cb2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryLiabilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryLiabilityAxis_ec3cd88b-f634-4b1c-ba97-fc58a09c2cb2" xlink:to="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFuelCostsMember_3d71ff24-fd95-4400-a1b9-4be777fea4f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFuelCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:to="loc_us-gaap_DeferredFuelCostsMember_3d71ff24-fd95-4400-a1b9-4be777fea4f6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_3ae39358-393b-42ee-b6b7-781c598a326c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementPlansCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:to="loc_us-gaap_PensionAndOtherPostretirementPlansCostsMember_3ae39358-393b-42ee-b6b7-781c598a326c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RemovalCostsMember_523a37c3-4d64-41c1-857d-e4a0a3720c0a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RemovalCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:to="loc_us-gaap_RemovalCostsMember_523a37c3-4d64-41c1-857d-e4a0a3720c0a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DeferredIncomeTaxChargesaMember_546c774a-7890-42cf-86f5-4f821b7548ef" xlink:href="bkh-20210331.xsd#bkh_DeferredIncomeTaxChargesaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:to="loc_bkh_DeferredIncomeTaxChargesaMember_546c774a-7890-42cf-86f5-4f821b7548ef" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherRegulatoryLiabilitiesMember_ecd27ceb-bde4-4fa2-b732-23a67492bf96" xlink:href="bkh-20210331.xsd#bkh_OtherRegulatoryLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryLiabilityDomain_4fc5b9a9-c147-4979-9983-5f558352a760" xlink:to="loc_bkh_OtherRegulatoryLiabilitiesMember_ecd27ceb-bde4-4fa2-b732-23a67492bf96" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersWinterStormUriDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RegulatoryMattersWinterStormUriDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersWinterStormUriDetails" xlink:type="extended" id="i05f87f90eafb449aad4d0eb2d1924564_RegulatoryMattersWinterStormUriDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_5bac7ba7-7c59-4c9d-90a6-088c3c2837f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_IncrementalFuelPurchasedPowerAndNaturalGasCosts_3f99ae2b-f141-4977-8828-6143dcc0a666" xlink:href="bkh-20210331.xsd#bkh_IncrementalFuelPurchasedPowerAndNaturalGasCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_5bac7ba7-7c59-4c9d-90a6-088c3c2837f7" xlink:to="loc_bkh_IncrementalFuelPurchasedPowerAndNaturalGasCosts_3f99ae2b-f141-4977-8828-6143dcc0a666" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_5937958b-18fd-40f4-800c-719f9d4b4c5d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_5bac7ba7-7c59-4c9d-90a6-088c3c2837f7" xlink:to="loc_us-gaap_RegulatoryAssets_5937958b-18fd-40f4-800c-719f9d4b4c5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_IncomeStatementImpacts_6c1940cf-f9fc-46e9-bb79-b97b48307eaf" xlink:href="bkh-20210331.xsd#bkh_IncomeStatementImpacts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_5bac7ba7-7c59-4c9d-90a6-088c3c2837f7" xlink:to="loc_bkh_IncomeStatementImpacts_6c1940cf-f9fc-46e9-bb79-b97b48307eaf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_3b9371f6-5e1d-473c-92af-10989fd6911c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_5bac7ba7-7c59-4c9d-90a6-088c3c2837f7" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_3b9371f6-5e1d-473c-92af-10989fd6911c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_5bac7ba7-7c59-4c9d-90a6-088c3c2837f7" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_2a8ee6c1-b306-41ec-9b3f-f8098481e17a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_2a8ee6c1-b306-41ec-9b3f-f8098481e17a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_2a8ee6c1-b306-41ec-9b3f-f8098481e17a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_2a8ee6c1-b306-41ec-9b3f-f8098481e17a" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_2a8ee6c1-b306-41ec-9b3f-f8098481e17a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_96fdcc5f-8313-4b2a-aa1b-bbc75fb4e557" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_2a8ee6c1-b306-41ec-9b3f-f8098481e17a" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_96fdcc5f-8313-4b2a-aa1b-bbc75fb4e557" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WinterStormUriMember_3e61b69f-dbe8-4f7a-bfd2-81162142c730" xlink:href="bkh-20210331.xsd#bkh_WinterStormUriMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_96fdcc5f-8313-4b2a-aa1b-bbc75fb4e557" xlink:to="loc_bkh_WinterStormUriMember_3e61b69f-dbe8-4f7a-bfd2-81162142c730" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_721a28a3-84ea-464b-928e-a78aa4c204b5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_721a28a3-84ea-464b-928e-a78aa4c204b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_721a28a3-84ea-464b-928e-a78aa4c204b5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_721a28a3-84ea-464b-928e-a78aa4c204b5" xlink:to="loc_us-gaap_SegmentDomain_721a28a3-84ea-464b-928e-a78aa4c204b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3002b2ef-5772-4f77-b6fe-5d5ca0e22e70" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_721a28a3-84ea-464b-928e-a78aa4c204b5" xlink:to="loc_us-gaap_SegmentDomain_3002b2ef-5772-4f77-b6fe-5d5ca0e22e70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_7015082d-1e81-42f1-bf79-26382a649601" xlink:href="bkh-20210331.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3002b2ef-5772-4f77-b6fe-5d5ca0e22e70" xlink:to="loc_bkh_ElectricUtilitiesMember_7015082d-1e81-42f1-bf79-26382a649601" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_0aa61714-e9ad-4f57-8a3a-a2e7f555a3f8" xlink:href="bkh-20210331.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3002b2ef-5772-4f77-b6fe-5d5ca0e22e70" xlink:to="loc_bkh_GasUtilitiesMember_0aa61714-e9ad-4f57-8a3a-a2e7f555a3f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_953a24f4-b055-41e9-9b22-fbf92e2defb8" xlink:href="bkh-20210331.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3002b2ef-5772-4f77-b6fe-5d5ca0e22e70" xlink:to="loc_bkh_PowerGenerationMember_953a24f4-b055-41e9-9b22-fbf92e2defb8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_4432f8d3-c5e9-4050-94b8-bc9a349e7995" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:to="loc_dei_LegalEntityAxis_4432f8d3-c5e9-4050-94b8-bc9a349e7995" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_4432f8d3-c5e9-4050-94b8-bc9a349e7995_default" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_4432f8d3-c5e9-4050-94b8-bc9a349e7995" xlink:to="loc_dei_EntityDomain_4432f8d3-c5e9-4050-94b8-bc9a349e7995_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_4432f8d3-c5e9-4050-94b8-bc9a349e7995" xlink:to="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyArkansasGasMember_447f5e2e-cf40-4106-ae75-0c563fdb7606" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyArkansasGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyArkansasGasMember_447f5e2e-cf40-4106-ae75-0c563fdb7606" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyColoradoGasMember_b78072f4-4735-4965-ab91-6e1b9720d620" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyColoradoGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyColoradoGasMember_b78072f4-4735-4965-ab91-6e1b9720d620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyIowaGasMember_652e17d6-1631-4c8e-ac4c-d0ddd6fbd5cd" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyIowaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyIowaGasMember_652e17d6-1631-4c8e-ac4c-d0ddd6fbd5cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyKansasGasMember_2388c44a-6d4a-4475-8132-96dbb28d77ef" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyKansasGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyKansasGasMember_2388c44a-6d4a-4475-8132-96dbb28d77ef" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyNebraskaGasMember_9acb3d98-824f-4c79-b387-02263dae51c0" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyNebraskaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyNebraskaGasMember_9acb3d98-824f-4c79-b387-02263dae51c0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyWyomingGasMember_6494decc-16ce-4349-89c5-828ab26731a4" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyWyomingGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyWyomingGasMember_6494decc-16ce-4349-89c5-828ab26731a4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyColoradoElectricMember_2f0424fb-ba59-4a8d-b05c-c80cf2f43f2e" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyColoradoElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyColoradoElectricMember_2f0424fb-ba59-4a8d-b05c-c80cf2f43f2e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergySouthDakotaElectricMember_4619cbc8-84bb-4f75-ae44-f4c278c3db21" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergySouthDakotaElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergySouthDakotaElectricMember_4619cbc8-84bb-4f75-ae44-f4c278c3db21" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyWyomingElectricMember_a978a146-3dbe-4fae-b5a6-f3c928ae671d" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyWyomingElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyWyomingElectricMember_a978a146-3dbe-4fae-b5a6-f3c928ae671d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyServicesMember_b87b27d6-f272-40d7-b892-eab2712b1e33" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_d817e7dc-9bbe-45b0-88c5-876239e60558" xlink:to="loc_bkh_BlackHillsEnergyServicesMember_b87b27d6-f272-40d7-b892-eab2712b1e33" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_ea759033-d203-4794-9773-eecd76748c4d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_ea759033-d203-4794-9773-eecd76748c4d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_ea759033-d203-4794-9773-eecd76748c4d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_ea759033-d203-4794-9773-eecd76748c4d" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_ea759033-d203-4794-9773-eecd76748c4d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_21d80f73-24ee-4f96-9718-d236bfb714f3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_ea759033-d203-4794-9773-eecd76748c4d" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_21d80f73-24ee-4f96-9718-d236bfb714f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WholesalePowerMarginImpactsMember_d095fbc1-7f01-42e2-ada5-da5c2a326d72" xlink:href="bkh-20210331.xsd#bkh_WholesalePowerMarginImpactsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21d80f73-24ee-4f96-9718-d236bfb714f3" xlink:to="loc_bkh_WholesalePowerMarginImpactsMember_d095fbc1-7f01-42e2-ada5-da5c2a326d72" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NonRecoverableFuelCostsMember_a4a5b396-612e-483c-8e5a-44bb9947eaaa" xlink:href="bkh-20210331.xsd#bkh_NonRecoverableFuelCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21d80f73-24ee-4f96-9718-d236bfb714f3" xlink:to="loc_bkh_NonRecoverableFuelCostsMember_a4a5b396-612e-483c-8e5a-44bb9947eaaa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_37d39dbb-65a2-4996-9efc-0bedbf24876e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21d80f73-24ee-4f96-9718-d236bfb714f3" xlink:to="loc_us-gaap_InterestExpenseMember_37d39dbb-65a2-4996-9efc-0bedbf24876e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLossMember_481b383f-06d8-4755-9067-9efa0eaf0a42" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_21d80f73-24ee-4f96-9718-d236bfb714f3" xlink:to="loc_us-gaap_OperatingIncomeLossMember_481b383f-06d8-4755-9067-9efa0eaf0a42" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4902db88-4d6b-40db-a4f4-fae30de321e2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:to="loc_us-gaap_DebtInstrumentAxis_4902db88-4d6b-40db-a4f4-fae30de321e2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4902db88-4d6b-40db-a4f4-fae30de321e2_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4902db88-4d6b-40db-a4f4-fae30de321e2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4902db88-4d6b-40db-a4f4-fae30de321e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_e2788a51-39ee-4b4c-a483-78c6a8fcdb09" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4902db88-4d6b-40db-a4f4-fae30de321e2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_e2788a51-39ee-4b4c-a483-78c6a8fcdb09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SeniorUnsecuredNotesDue2021Member_cc8cd9e4-703c-4dec-b7e2-0737acaa75a6" xlink:href="bkh-20210331.xsd#bkh_SeniorUnsecuredNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_e2788a51-39ee-4b4c-a483-78c6a8fcdb09" xlink:to="loc_bkh_SeniorUnsecuredNotesDue2021Member_cc8cd9e4-703c-4dec-b7e2-0737acaa75a6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_6c9400e7-d3c7-4d85-8f3f-4ab188020600" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_e5eda9f5-283d-4111-b0a5-195621e6e518" xlink:to="loc_us-gaap_RegulatoryAssetAxis_6c9400e7-d3c7-4d85-8f3f-4ab188020600" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_6c9400e7-d3c7-4d85-8f3f-4ab188020600_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_6c9400e7-d3c7-4d85-8f3f-4ab188020600" xlink:to="loc_us-gaap_RegulatoryAssetDomain_6c9400e7-d3c7-4d85-8f3f-4ab188020600_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_ea254991-7681-4b83-a2b8-d13f6206ff08" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_6c9400e7-d3c7-4d85-8f3f-4ab188020600" xlink:to="loc_us-gaap_RegulatoryAssetDomain_ea254991-7681-4b83-a2b8-d13f6206ff08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StormCostsMember_d7d79e38-124c-4c00-82d2-14bd30472f20" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StormCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_ea254991-7681-4b83-a2b8-d13f6206ff08" xlink:to="loc_us-gaap_StormCostsMember_d7d79e38-124c-4c00-82d2-14bd30472f20" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFuelCostsMember_6471c2fb-3215-436e-8002-25fbe2496ddc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFuelCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_ea254991-7681-4b83-a2b8-d13f6206ff08" xlink:to="loc_us-gaap_DeferredFuelCostsMember_6471c2fb-3215-436e-8002-25fbe2496ddc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetRecoverableGasCostsMember_726221ee-9177-4749-b642-85e6f813d962" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetRecoverableGasCostsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_ea254991-7681-4b83-a2b8-d13f6206ff08" xlink:to="loc_us-gaap_AssetRecoverableGasCostsMember_726221ee-9177-4749-b642-85e6f813d962" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RegulatoryMattersRateReviewDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RegulatoryMattersRateReviewDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RegulatoryMattersRateReviewDetails" xlink:type="extended" id="i91b11c9ff9344514812553846329807b_RegulatoryMattersRateReviewDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SettlementOfPlanToProvideTCJARelatedCustomerBillingCreditsToItsCustomers_542ccd74-6965-43c3-8080-67896eacc4ff" xlink:href="bkh-20210331.xsd#bkh_SettlementOfPlanToProvideTCJARelatedCustomerBillingCreditsToItsCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_bkh_SettlementOfPlanToProvideTCJARelatedCustomerBillingCreditsToItsCustomers_542ccd74-6965-43c3-8080-67896eacc4ff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit_79d61ac1-a998-4ac9-bace-dfa947cec7b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_us-gaap_TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit_79d61ac1-a998-4ac9-bace-dfa947cec7b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments_1cfa731a-d7ec-48a0-aa6e-cd24678efd29" xlink:href="bkh-20210331.xsd#bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_bkh_PublicUtilitiesLengthOfNaturalGasPipelineToReceiveInfrastructureInvestments_1cfa731a-d7ec-48a0-aa6e-cd24678efd29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegretyRiderMovedToBaseRates_f38e7803-c915-4e73-9d4e-982d737aa494" xlink:href="bkh-20210331.xsd#bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegretyRiderMovedToBaseRates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_bkh_PublicUtilitiesAmountOfSystemSafetyAndIntegretyRiderMovedToBaseRates_f38e7803-c915-4e73-9d4e-982d737aa494" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount_bee60e49-c08c-4158-a837-5273357b23e5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount_bee60e49-c08c-4158-a837-5273357b23e5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage_b8495fa0-9ce1-4f73-8a18-ff1d1d1fdb6a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage_b8495fa0-9ce1-4f73-8a18-ff1d1d1fdb6a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage_e8dfa2e6-7f94-44bf-903e-0f0741d17bed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_us-gaap_PublicUtilitiesApprovedDebtCapitalStructurePercentage_e8dfa2e6-7f94-44bf-903e-0f0741d17bed" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage_578493ab-1e69-4308-a45c-888d4fa72cb5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage_578493ab-1e69-4308-a45c-888d4fa72cb5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PublicUtilitiesTermExtensionOfSystemSafteyAndIntegrityRider_6e9d4bd8-28c5-4277-81f5-a683a1edfb8f" xlink:href="bkh-20210331.xsd#bkh_PublicUtilitiesTermExtensionOfSystemSafteyAndIntegrityRider"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_bkh_PublicUtilitiesTermExtensionOfSystemSafteyAndIntegrityRider_6e9d4bd8-28c5-4277-81f5-a683a1edfb8f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_7624af4a-d1e2-4725-bf8d-7cb38b942215" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesGeneralDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresLineItems_2d40a125-b417-4f13-9a96-29e5eeff0377" xlink:to="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_7624af4a-d1e2-4725-bf8d-7cb38b942215" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_7e18d961-a136-49f3-a7e7-9281ed798c42" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_7624af4a-d1e2-4725-bf8d-7cb38b942215" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_7e18d961-a136-49f3-a7e7-9281ed798c42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_7e18d961-a136-49f3-a7e7-9281ed798c42_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_7e18d961-a136-49f3-a7e7-9281ed798c42" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_7e18d961-a136-49f3-a7e7-9281ed798c42_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_8234393d-eb06-4744-a1f8-d5413ce8e1dd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilitiesRegulatoryProceedingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingAxis_7e18d961-a136-49f3-a7e7-9281ed798c42" xlink:to="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_8234393d-eb06-4744-a1f8-d5413ce8e1dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_RateReviewFiledwiththeRegulatoryAgencyMember_2d7176d9-a083-4c45-91cf-dd85862e5c07" xlink:href="bkh-20210331.xsd#bkh_RateReviewFiledwiththeRegulatoryAgencyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_8234393d-eb06-4744-a1f8-d5413ce8e1dd" xlink:to="loc_bkh_RateReviewFiledwiththeRegulatoryAgencyMember_2d7176d9-a083-4c45-91cf-dd85862e5c07" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_RateReviewDismissedByRegulatoryAgencyMember_bd39dfe9-bb33-4576-9823-30c54d094b2c" xlink:href="bkh-20210331.xsd#bkh_RateReviewDismissedByRegulatoryAgencyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PublicUtilitiesRegulatoryProceedingDomain_8234393d-eb06-4744-a1f8-d5413ce8e1dd" xlink:to="loc_bkh_RateReviewDismissedByRegulatoryAgencyMember_bd39dfe9-bb33-4576-9823-30c54d094b2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyAxis_84393d3c-afe3-4bb7-9df6-5250e3e00a9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAgencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_7624af4a-d1e2-4725-bf8d-7cb38b942215" xlink:to="loc_us-gaap_RegulatoryAgencyAxis_84393d3c-afe3-4bb7-9df6-5250e3e00a9e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_84393d3c-afe3-4bb7-9df6-5250e3e00a9e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_84393d3c-afe3-4bb7-9df6-5250e3e00a9e" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_84393d3c-afe3-4bb7-9df6-5250e3e00a9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAgencyDomain_f5fd13df-60c5-4d57-bd6d-07757b27d17b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAgencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAgencyAxis_84393d3c-afe3-4bb7-9df6-5250e3e00a9e" xlink:to="loc_us-gaap_RegulatoryAgencyDomain_f5fd13df-60c5-4d57-bd6d-07757b27d17b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoPublicUtilitiesCommissionCPUCMember_01782215-05af-41dc-98a4-30ea90ed5c93" xlink:href="bkh-20210331.xsd#bkh_ColoradoPublicUtilitiesCommissionCPUCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_f5fd13df-60c5-4d57-bd6d-07757b27d17b" xlink:to="loc_bkh_ColoradoPublicUtilitiesCommissionCPUCMember_01782215-05af-41dc-98a4-30ea90ed5c93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NebraskaPublicServiceCommissionNPSCMember_35428655-1890-4254-bfae-725a69c8faf3" xlink:href="bkh-20210331.xsd#bkh_NebraskaPublicServiceCommissionNPSCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_f5fd13df-60c5-4d57-bd6d-07757b27d17b" xlink:to="loc_bkh_NebraskaPublicServiceCommissionNPSCMember_35428655-1890-4254-bfae-725a69c8faf3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NebraskaPublcServiceCommissionNPSCMember_1cb40802-e55b-4015-9dea-d4e48f2c453c" xlink:href="bkh-20210331.xsd#bkh_NebraskaPublcServiceCommissionNPSCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAgencyDomain_f5fd13df-60c5-4d57-bd6d-07757b27d17b" xlink:to="loc_bkh_NebraskaPublcServiceCommissionNPSCMember_1cb40802-e55b-4015-9dea-d4e48f2c453c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_969c8969-ebff-4e2f-8af0-d5a333321d7f" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PublicUtilitiesGeneralDisclosuresTable_7624af4a-d1e2-4725-bf8d-7cb38b942215" xlink:to="loc_dei_LegalEntityAxis_969c8969-ebff-4e2f-8af0-d5a333321d7f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_969c8969-ebff-4e2f-8af0-d5a333321d7f_default" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_969c8969-ebff-4e2f-8af0-d5a333321d7f" xlink:to="loc_dei_EntityDomain_969c8969-ebff-4e2f-8af0-d5a333321d7f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_3b4a91cc-bf84-46da-b666-4996cb34881e" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_969c8969-ebff-4e2f-8af0-d5a333321d7f" xlink:to="loc_dei_EntityDomain_3b4a91cc-bf84-46da-b666-4996cb34881e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyColoradoElectricMember_8094345d-d012-45d7-8865-e012ad064616" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyColoradoElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_3b4a91cc-bf84-46da-b666-4996cb34881e" xlink:to="loc_bkh_BlackHillsEnergyColoradoElectricMember_8094345d-d012-45d7-8865-e012ad064616" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyColoradoGasMember_fa9a3c54-48de-4ad1-a934-b3e92dec3c6f" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyColoradoGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_3b4a91cc-bf84-46da-b666-4996cb34881e" xlink:to="loc_bkh_BlackHillsEnergyColoradoGasMember_fa9a3c54-48de-4ad1-a934-b3e92dec3c6f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_BlackHillsEnergyNebraskaGasMember_743e80af-caa9-48b7-a049-12e55529b2b0" xlink:href="bkh-20210331.xsd#bkh_BlackHillsEnergyNebraskaGasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_3b4a91cc-bf84-46da-b666-4996cb34881e" xlink:to="loc_bkh_BlackHillsEnergyNebraskaGasMember_743e80af-caa9-48b7-a049-12e55529b2b0" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CommitmentsContingenciesandGuarantees" xlink:type="simple" xlink:href="bkh-20210331.xsd#CommitmentsContingenciesandGuarantees"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CommitmentsContingenciesandGuarantees" xlink:type="extended" id="i6472a37279f243a98989dfe992728598_CommitmentsContingenciesandGuarantees"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/CommitmentsContingenciesandGuaranteesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#CommitmentsContingenciesandGuaranteesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/CommitmentsContingenciesandGuaranteesDetails" xlink:type="extended" id="ifdedebad3c134cc19154974187159072_CommitmentsContingenciesandGuaranteesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_61078fa8-72db-4c30-abbd-0279d18717ae" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NumberOfMegawattsCapacityPurchased_e7a8abc2-a9a6-4029-91c0-721da28679e5" xlink:href="bkh-20210331.xsd#bkh_NumberOfMegawattsCapacityPurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_61078fa8-72db-4c30-abbd-0279d18717ae" xlink:to="loc_bkh_NumberOfMegawattsCapacityPurchased_e7a8abc2-a9a6-4029-91c0-721da28679e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PurchasePowerAgreementSetToExpireAfterACertainNumberOfYearsFollowingCompletionOfTheFacility_e86d3058-551c-437b-bc71-1407f1b92d77" xlink:href="bkh-20210331.xsd#bkh_PurchasePowerAgreementSetToExpireAfterACertainNumberOfYearsFollowingCompletionOfTheFacility"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_61078fa8-72db-4c30-abbd-0279d18717ae" xlink:to="loc_bkh_PurchasePowerAgreementSetToExpireAfterACertainNumberOfYearsFollowingCompletionOfTheFacility_e86d3058-551c-437b-bc71-1407f1b92d77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_74558cb1-fad2-4dd1-a06c-4ee4adf63796" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecordedUnconditionalPurchaseObligationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems_61078fa8-72db-4c30-abbd-0279d18717ae" xlink:to="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_74558cb1-fad2-4dd1-a06c-4ee4adf63796" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_04252fae-3c3b-4fb7-aeab-9ee78f7dafe9" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_74558cb1-fad2-4dd1-a06c-4ee4adf63796" xlink:to="loc_dei_LegalEntityAxis_04252fae-3c3b-4fb7-aeab-9ee78f7dafe9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_04252fae-3c3b-4fb7-aeab-9ee78f7dafe9_default" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_04252fae-3c3b-4fb7-aeab-9ee78f7dafe9" xlink:to="loc_dei_EntityDomain_04252fae-3c3b-4fb7-aeab-9ee78f7dafe9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_52a5cca7-7ed3-4813-a9d4-00d1aa4de639" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_04252fae-3c3b-4fb7-aeab-9ee78f7dafe9" xlink:to="loc_dei_EntityDomain_52a5cca7-7ed3-4813-a9d4-00d1aa4de639" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoElectricMember_12e435d2-4ce4-46e3-8cee-7668ce34e5a0" xlink:href="bkh-20210331.xsd#bkh_ColoradoElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_52a5cca7-7ed3-4813-a9d4-00d1aa4de639" xlink:to="loc_bkh_ColoradoElectricMember_12e435d2-4ce4-46e3-8cee-7668ce34e5a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_210390f3-36d1-49a8-96de-ea8100a9b465" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_74558cb1-fad2-4dd1-a06c-4ee4adf63796" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_210390f3-36d1-49a8-96de-ea8100a9b465" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_210390f3-36d1-49a8-96de-ea8100a9b465_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_210390f3-36d1-49a8-96de-ea8100a9b465" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_210390f3-36d1-49a8-96de-ea8100a9b465_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_0f984358-1918-4e12-9179-7a0c60e1abf4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermContractForPurchaseOfElectricPowerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerAxis_210390f3-36d1-49a8-96de-ea8100a9b465" xlink:to="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_0f984358-1918-4e12-9179-7a0c60e1abf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TCColoradoSolarLLCMember_1c28bf45-f6f2-439a-acd8-533831bdfc45" xlink:href="bkh-20210331.xsd#bkh_TCColoradoSolarLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermContractForPurchaseOfElectricPowerDomain_0f984358-1918-4e12-9179-7a0c60e1abf4" xlink:to="loc_bkh_TCColoradoSolarLLCMember_1c28bf45-f6f2-439a-acd8-533831bdfc45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelTypeAxis_ba28db02-8c1c-459b-ac9b-aa3205274bbc" xlink:href="bkh-20210331.xsd#bkh_FuelTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_UnrecordedUnconditionalPurchaseObligationTable_74558cb1-fad2-4dd1-a06c-4ee4adf63796" xlink:to="loc_bkh_FuelTypeAxis_ba28db02-8c1c-459b-ac9b-aa3205274bbc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelTypeDomain_ba28db02-8c1c-459b-ac9b-aa3205274bbc_default" xlink:href="bkh-20210331.xsd#bkh_FuelTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_bkh_FuelTypeAxis_ba28db02-8c1c-459b-ac9b-aa3205274bbc" xlink:to="loc_bkh_FuelTypeDomain_ba28db02-8c1c-459b-ac9b-aa3205274bbc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelTypeDomain_8c522566-ce87-40de-a320-2c6a9026150e" xlink:href="bkh-20210331.xsd#bkh_FuelTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_bkh_FuelTypeAxis_ba28db02-8c1c-459b-ac9b-aa3205274bbc" xlink:to="loc_bkh_FuelTypeDomain_8c522566-ce87-40de-a320-2c6a9026150e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SolarMember_9f4ec891-d51f-4a89-b872-14323bd858f8" xlink:href="bkh-20210331.xsd#bkh_SolarMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_FuelTypeDomain_8c522566-ce87-40de-a320-2c6a9026150e" xlink:to="loc_bkh_SolarMember_9f4ec891-d51f-4a89-b872-14323bd858f8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/Revenue" xlink:type="simple" xlink:href="bkh-20210331.xsd#Revenue"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/Revenue" xlink:type="extended" id="ic8fbac39dea549d8a6d73ff7de87ac65_Revenue"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RevenueTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#RevenueTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RevenueTables" xlink:type="extended" id="i979994f65c92407d9bbb4c064f91583f_RevenueTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/DisaggregationofRevenueDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#DisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/DisaggregationofRevenueDetails" xlink:type="extended" id="i31a9e50c5a864c91b6db780f2b46a140_DisaggregationofRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_119b107b-9073-4bbf-83ed-c115b9482444" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_695fbd31-8d29-4db8-82cd-17682ce86e39" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_119b107b-9073-4bbf-83ed-c115b9482444" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_695fbd31-8d29-4db8-82cd-17682ce86e39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_9932f833-f348-4f00-a4ea-58d0381b3476" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_119b107b-9073-4bbf-83ed-c115b9482444" xlink:to="loc_us-gaap_Revenues_9932f833-f348-4f00-a4ea-58d0381b3476" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_119b107b-9073-4bbf-83ed-c115b9482444" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01afe964-23b4-414b-a40c-4d5b1e3448de" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01afe964-23b4-414b-a40c-4d5b1e3448de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01afe964-23b4-414b-a40c-4d5b1e3448de_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01afe964-23b4-414b-a40c-4d5b1e3448de" xlink:to="loc_us-gaap_SegmentDomain_01afe964-23b4-414b-a40c-4d5b1e3448de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e93c48c8-f5df-4cac-98f3-9744ca45712e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01afe964-23b4-414b-a40c-4d5b1e3448de" xlink:to="loc_us-gaap_SegmentDomain_e93c48c8-f5df-4cac-98f3-9744ca45712e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_9062f768-1efe-4324-a5b6-b9eeca25909f" xlink:href="bkh-20210331.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e93c48c8-f5df-4cac-98f3-9744ca45712e" xlink:to="loc_bkh_ElectricUtilitiesMember_9062f768-1efe-4324-a5b6-b9eeca25909f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_8f2ac63d-083e-49e8-b305-a3b50fc2d534" xlink:href="bkh-20210331.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e93c48c8-f5df-4cac-98f3-9744ca45712e" xlink:to="loc_bkh_GasUtilitiesMember_8f2ac63d-083e-49e8-b305-a3b50fc2d534" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_96dc7d4d-5f92-447c-9c05-27f0bb671fc8" xlink:href="bkh-20210331.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e93c48c8-f5df-4cac-98f3-9744ca45712e" xlink:to="loc_bkh_PowerGenerationMember_96dc7d4d-5f92-447c-9c05-27f0bb671fc8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MiningMember_51f81471-d033-4250-a1af-536fde738180" xlink:href="bkh-20210331.xsd#bkh_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e93c48c8-f5df-4cac-98f3-9744ca45712e" xlink:to="loc_bkh_MiningMember_51f81471-d033-4250-a1af-536fde738180" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_4c34c83b-bdeb-4900-92aa-f6974021e245" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:to="loc_srt_ConsolidationItemsAxis_4c34c83b-bdeb-4900-92aa-f6974021e245" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_4c34c83b-bdeb-4900-92aa-f6974021e245_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_4c34c83b-bdeb-4900-92aa-f6974021e245" xlink:to="loc_srt_ConsolidationItemsDomain_4c34c83b-bdeb-4900-92aa-f6974021e245_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_d566669f-190b-44e7-b0a5-5744d5ceafb0" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_4c34c83b-bdeb-4900-92aa-f6974021e245" xlink:to="loc_srt_ConsolidationItemsDomain_d566669f-190b-44e7-b0a5-5744d5ceafb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_02490af1-4e14-436c-a164-d8916c29eb2e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_d566669f-190b-44e7-b0a5-5744d5ceafb0" xlink:to="loc_us-gaap_IntersegmentEliminationMember_02490af1-4e14-436c-a164-d8916c29eb2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_5077d26d-bc9b-4b64-9260-d8f4af2cbd40" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:to="loc_srt_MajorCustomersAxis_5077d26d-bc9b-4b64-9260-d8f4af2cbd40" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_5077d26d-bc9b-4b64-9260-d8f4af2cbd40_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_5077d26d-bc9b-4b64-9260-d8f4af2cbd40" xlink:to="loc_srt_NameOfMajorCustomerDomain_5077d26d-bc9b-4b64-9260-d8f4af2cbd40_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_5077d26d-bc9b-4b64-9260-d8f4af2cbd40" xlink:to="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_RetailElectricNaturalGasandCoalMember_f7a91182-c82e-48bf-81d5-d3d9f60d085f" xlink:href="bkh-20210331.xsd#bkh_RetailElectricNaturalGasandCoalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:to="loc_bkh_RetailElectricNaturalGasandCoalMember_f7a91182-c82e-48bf-81d5-d3d9f60d085f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TransportationMember_5dc98c57-33fb-47e4-a620-c8eb2e364f56" xlink:href="bkh-20210331.xsd#bkh_TransportationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:to="loc_bkh_TransportationMember_5dc98c57-33fb-47e4-a620-c8eb2e364f56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WholesaleMember_7bae7006-0f7c-4372-864f-b3ffac08be70" xlink:href="bkh-20210331.xsd#bkh_WholesaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:to="loc_bkh_WholesaleMember_7bae7006-0f7c-4372-864f-b3ffac08be70" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MarketOffSystemSalesMember_8bb832ba-f2ea-41af-a97e-b168a5b6ed44" xlink:href="bkh-20210331.xsd#bkh_MarketOffSystemSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:to="loc_bkh_MarketOffSystemSalesMember_8bb832ba-f2ea-41af-a97e-b168a5b6ed44" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TransmissionOtherMember_505e2828-361b-4006-bb43-25b514daf144" xlink:href="bkh-20210331.xsd#bkh_TransmissionOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f1433c7d-8291-45c7-ba29-9b304b5d816d" xlink:to="loc_bkh_TransmissionOtherMember_505e2828-361b-4006-bb43-25b514daf144" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_4f1fc7d1-fb74-4718-a141-6b47eedd7585" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:to="loc_srt_ProductOrServiceAxis_4f1fc7d1-fb74-4718-a141-6b47eedd7585" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_4f1fc7d1-fb74-4718-a141-6b47eedd7585_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_4f1fc7d1-fb74-4718-a141-6b47eedd7585" xlink:to="loc_srt_ProductsAndServicesDomain_4f1fc7d1-fb74-4718-a141-6b47eedd7585_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_522220e0-15a8-46cf-9b69-250ede0779dd" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_4f1fc7d1-fb74-4718-a141-6b47eedd7585" xlink:to="loc_srt_ProductsAndServicesDomain_522220e0-15a8-46cf-9b69-250ede0779dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherMember_4dab7367-3d53-4d8b-8192-57994c49f2a8" xlink:href="bkh-20210331.xsd#bkh_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_522220e0-15a8-46cf-9b69-250ede0779dd" xlink:to="loc_bkh_OtherMember_4dab7367-3d53-4d8b-8192-57994c49f2a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_4ccb32e9-7f25-4189-b6d5-515ec3b2454c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_b300e283-c01c-4161-a92f-a902e25192ea" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_4ccb32e9-7f25-4189-b6d5-515ec3b2454c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_4ccb32e9-7f25-4189-b6d5-515ec3b2454c_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_4ccb32e9-7f25-4189-b6d5-515ec3b2454c" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_4ccb32e9-7f25-4189-b6d5-515ec3b2454c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_e0ec373f-ed4c-419f-ad03-a2d4dfb1d5a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_4ccb32e9-7f25-4189-b6d5-515ec3b2454c" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_e0ec373f-ed4c-419f-ad03-a2d4dfb1d5a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_f9244386-c81a-4024-be98-9d80f80bbc0a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_e0ec373f-ed4c-419f-ad03-a2d4dfb1d5a0" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_f9244386-c81a-4024-be98-9d80f80bbc0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_2de7e5be-3ff7-4e77-9d3c-c59660a9db46" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_e0ec373f-ed4c-419f-ad03-a2d4dfb1d5a0" xlink:to="loc_us-gaap_TransferredOverTimeMember_2de7e5be-3ff7-4e77-9d3c-c59660a9db46" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/Financing" xlink:type="simple" xlink:href="bkh-20210331.xsd#Financing"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/Financing" xlink:type="extended" id="i8c4530ef27c94b2fbb66fc25fe3ece52_Financing"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#FinancingTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingTables" xlink:type="extended" id="i8460be69f6a640e1bf9561e4e1721d42_FinancingTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingScheduleofShorttermDebtandNarrativeDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#FinancingScheduleofShorttermDebtandNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingScheduleofShorttermDebtandNarrativeDetails" xlink:type="extended" id="idc19b2079b9d47408bc22b38c1d92138_FinancingScheduleofShorttermDebtandNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_f0773862-fccc-45f4-83b8-559c7873b300" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_90c50493-5a03-4583-aeeb-dc7912296b64" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_f0773862-fccc-45f4-83b8-559c7873b300" xlink:to="loc_us-gaap_ShortTermBorrowings_90c50493-5a03-4583-aeeb-dc7912296b64" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_9ee84367-b1de-410e-8a98-bc882f935452" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_f0773862-fccc-45f4-83b8-559c7873b300" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_9ee84367-b1de-410e-8a98-bc882f935452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_45aab360-0d06-42ae-8f1a-3c6d4416b0b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_f0773862-fccc-45f4-83b8-559c7873b300" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_45aab360-0d06-42ae-8f1a-3c6d4416b0b1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_4c8afc25-9403-42b6-9a7c-092c7f46881b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_45aab360-0d06-42ae-8f1a-3c6d4416b0b1" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_4c8afc25-9403-42b6-9a7c-092c7f46881b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_4c8afc25-9403-42b6-9a7c-092c7f46881b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_4c8afc25-9403-42b6-9a7c-092c7f46881b" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_4c8afc25-9403-42b6-9a7c-092c7f46881b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_0662675a-d10d-4cbf-b677-0c882491c061" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_4c8afc25-9403-42b6-9a7c-092c7f46881b" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_0662675a-d10d-4cbf-b677-0c882491c061" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_TermLoanMember_d6313c12-2019-4620-bd32-93036d2df2ef" xlink:href="bkh-20210331.xsd#bkh_TermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_0662675a-d10d-4cbf-b677-0c882491c061" xlink:to="loc_bkh_TermLoanMember_d6313c12-2019-4620-bd32-93036d2df2ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_64554ab2-3ddc-430a-8317-c9fb3a432376" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_0662675a-d10d-4cbf-b677-0c882491c061" xlink:to="loc_us-gaap_CommercialPaperMember_64554ab2-3ddc-430a-8317-c9fb3a432376" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_1c592129-a86f-4f09-8adf-084cd6631933" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_45aab360-0d06-42ae-8f1a-3c6d4416b0b1" xlink:to="loc_us-gaap_CreditFacilityAxis_1c592129-a86f-4f09-8adf-084cd6631933" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_1c592129-a86f-4f09-8adf-084cd6631933_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_1c592129-a86f-4f09-8adf-084cd6631933" xlink:to="loc_us-gaap_CreditFacilityDomain_1c592129-a86f-4f09-8adf-084cd6631933_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_33e2670a-625b-49a5-b05f-ec254335a913" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_1c592129-a86f-4f09-8adf-084cd6631933" xlink:to="loc_us-gaap_CreditFacilityDomain_33e2670a-625b-49a5-b05f-ec254335a913" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_45079669-46f9-42d3-a0f1-27dc8660f42c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_33e2670a-625b-49a5-b05f-ec254335a913" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_45079669-46f9-42d3-a0f1-27dc8660f42c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingTermLoanDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#FinancingTermLoanDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingTermLoanDetails" xlink:type="extended" id="iae136dd1f53d4ca2a81b317dd2d2a796_FinancingTermLoanDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_69dae76c-fdf2-4f0c-8262-764020240678" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_DebtInstrumentTerm_69dae76c-fdf2-4f0c-8262-764020240678" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_dea0579c-6770-4358-8906-78a9034e70ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_dea0579c-6770-4358-8906-78a9034e70ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_df1f2cb4-3e7f-4eec-b82c-5a7b1f5344cc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_df1f2cb4-3e7f-4eec-b82c-5a7b1f5344cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_7fa359f7-9659-4b97-80d7-3dcd1b6d4090" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_7fa359f7-9659-4b97-80d7-3dcd1b6d4090" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfOtherShortTermDebt_a39c51ea-fbbd-4cfa-9db7-90d8498c78f8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfOtherShortTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_RepaymentsOfOtherShortTermDebt_a39c51ea-fbbd-4cfa-9db7-90d8498c78f8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtPercentageBearingVariableInterestRate_0acdd684-7488-428b-ac32-13072812a640" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtPercentageBearingVariableInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_ShortTermDebtPercentageBearingVariableInterestRate_0acdd684-7488-428b-ac32-13072812a640" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_9ac530a1-4795-48f5-95d9-bba5e8a4bab5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_e9a1929f-0e27-42ca-98c1-9bdd11341707" xlink:to="loc_us-gaap_StatementTable_9ac530a1-4795-48f5-95d9-bba5e8a4bab5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_b1d00c18-06fc-45e5-951f-b43255462829" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9ac530a1-4795-48f5-95d9-bba5e8a4bab5" xlink:to="loc_us-gaap_DebtInstrumentAxis_b1d00c18-06fc-45e5-951f-b43255462829" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b1d00c18-06fc-45e5-951f-b43255462829_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_b1d00c18-06fc-45e5-951f-b43255462829" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b1d00c18-06fc-45e5-951f-b43255462829_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_8d1f4eb0-531b-4af8-969d-6c7c122c8ff1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_b1d00c18-06fc-45e5-951f-b43255462829" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_8d1f4eb0-531b-4af8-969d-6c7c122c8ff1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_SeniorUnsecuredNotesDue2021Member_d0bdf34c-4164-4d4b-bcd5-30d9a1c7ed09" xlink:href="bkh-20210331.xsd#bkh_SeniorUnsecuredNotesDue2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_8d1f4eb0-531b-4af8-969d-6c7c122c8ff1" xlink:to="loc_bkh_SeniorUnsecuredNotesDue2021Member_d0bdf34c-4164-4d4b-bcd5-30d9a1c7ed09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_a5f381ac-bb81-48ef-9006-db657acf5159" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_9ac530a1-4795-48f5-95d9-bba5e8a4bab5" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_a5f381ac-bb81-48ef-9006-db657acf5159" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_a5f381ac-bb81-48ef-9006-db657acf5159_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_a5f381ac-bb81-48ef-9006-db657acf5159" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_a5f381ac-bb81-48ef-9006-db657acf5159_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_7db6f669-7aca-4cd5-b6fe-aeb1d192d9d2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_a5f381ac-bb81-48ef-9006-db657acf5159" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_7db6f669-7aca-4cd5-b6fe-aeb1d192d9d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_cf367f0e-e195-4294-ae62-6f331a369b04" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_7db6f669-7aca-4cd5-b6fe-aeb1d192d9d2" xlink:to="loc_us-gaap_LineOfCreditMember_cf367f0e-e195-4294-ae62-6f331a369b04" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingRevolvingCreditFacilityandCPProgramDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#FinancingRevolvingCreditFacilityandCPProgramDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingRevolvingCreditFacilityandCPProgramDetails" xlink:type="extended" id="i9ae86168a2d3423c858b514b8dd909e9_FinancingRevolvingCreditFacilityandCPProgramDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b1d033d1-b4d4-4c06-8b10-733fdc336493" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NetPaymentsBorrowingsOfRevolvingCreditFacilityAndCommercialPaperProgram_3f95bbea-0f08-4f2b-9820-c7ffcb015cd5" xlink:href="bkh-20210331.xsd#bkh_NetPaymentsBorrowingsOfRevolvingCreditFacilityAndCommercialPaperProgram"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b1d033d1-b4d4-4c06-8b10-733fdc336493" xlink:to="loc_bkh_NetPaymentsBorrowingsOfRevolvingCreditFacilityAndCommercialPaperProgram_3f95bbea-0f08-4f2b-9820-c7ffcb015cd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_21a72097-0e45-44f6-9443-09e3de972c2e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b1d033d1-b4d4-4c06-8b10-733fdc336493" xlink:to="loc_us-gaap_ShortTermDebtWeightedAverageInterestRate_21a72097-0e45-44f6-9443-09e3de972c2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_bbe46726-1f8b-4c65-b579-d5041d2e2c52" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b1d033d1-b4d4-4c06-8b10-733fdc336493" xlink:to="loc_us-gaap_StatementTable_bbe46726-1f8b-4c65-b579-d5041d2e2c52" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_5546c60f-7e42-41a0-9ec9-23330bbfb4b9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_bbe46726-1f8b-4c65-b579-d5041d2e2c52" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_5546c60f-7e42-41a0-9ec9-23330bbfb4b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_5546c60f-7e42-41a0-9ec9-23330bbfb4b9_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_5546c60f-7e42-41a0-9ec9-23330bbfb4b9" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_5546c60f-7e42-41a0-9ec9-23330bbfb4b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_3cfb52fa-fdca-4e83-b287-937ded324f88" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_5546c60f-7e42-41a0-9ec9-23330bbfb4b9" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_3cfb52fa-fdca-4e83-b287-937ded324f88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_bde93ff9-e0fc-4e9f-b55c-5bbfd086fb53" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_3cfb52fa-fdca-4e83-b287-937ded324f88" xlink:to="loc_us-gaap_CommercialPaperMember_bde93ff9-e0fc-4e9f-b55c-5bbfd086fb53" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FinancingDebtCovenantsDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#FinancingDebtCovenantsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FinancingDebtCovenantsDetails" xlink:type="extended" id="ia7b8fc5c22354ca1a878f617891b6132_FinancingDebtCovenantsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_638dcb6d-acc8-4cfb-b707-ec64f8d574b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DebtInstrumentConsolidatedIndebtednessToCapitalizationRatioRequirementForTheNextFiscalYear_883c99c9-72ca-4437-8e5b-d2121f542cef" xlink:href="bkh-20210331.xsd#bkh_DebtInstrumentConsolidatedIndebtednessToCapitalizationRatioRequirementForTheNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_638dcb6d-acc8-4cfb-b707-ec64f8d574b1" xlink:to="loc_bkh_DebtInstrumentConsolidatedIndebtednessToCapitalizationRatioRequirementForTheNextFiscalYear_883c99c9-72ca-4437-8e5b-d2121f542cef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RatioOfIndebtednessToNetCapital1_8b31de50-93b4-4d62-a9aa-d7e9644b5e68" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RatioOfIndebtednessToNetCapital1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_638dcb6d-acc8-4cfb-b707-ec64f8d574b1" xlink:to="loc_us-gaap_RatioOfIndebtednessToNetCapital1_8b31de50-93b4-4d62-a9aa-d7e9644b5e68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_54ced2d7-3e71-4f07-804a-6e2d15351582" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_638dcb6d-acc8-4cfb-b707-ec64f8d574b1" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_54ced2d7-3e71-4f07-804a-6e2d15351582" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_89595361-9c4b-4842-8f6f-e530db56e142" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_54ced2d7-3e71-4f07-804a-6e2d15351582" xlink:to="loc_srt_RangeAxis_89595361-9c4b-4842-8f6f-e530db56e142" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_89595361-9c4b-4842-8f6f-e530db56e142_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_89595361-9c4b-4842-8f6f-e530db56e142" xlink:to="loc_srt_RangeMember_89595361-9c4b-4842-8f6f-e530db56e142_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_42cbb11c-740e-40d8-b6b9-66b47ee86d75" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_89595361-9c4b-4842-8f6f-e530db56e142" xlink:to="loc_srt_RangeMember_42cbb11c-740e-40d8-b6b9-66b47ee86d75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_77f69968-ee77-46e9-863d-59fbab19e15e" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_42cbb11c-740e-40d8-b6b9-66b47ee86d75" xlink:to="loc_srt_MaximumMember_77f69968-ee77-46e9-863d-59fbab19e15e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EarningsPerShare" xlink:type="simple" xlink:href="bkh-20210331.xsd#EarningsPerShare"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EarningsPerShare" xlink:type="extended" id="i2f2b185e1e34480c9125cdb9e02b7c7a_EarningsPerShare"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EarningsPerShareTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#EarningsPerShareTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EarningsPerShareTables" xlink:type="extended" id="if4d4a0f75ec6441186771c3017372183_EarningsPerShareTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EarningsPerShareEarningsPerShareReconciliationDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#EarningsPerShareEarningsPerShareReconciliationDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EarningsPerShareEarningsPerShareReconciliationDetails" xlink:type="extended" id="i63c24b5813cd4f56a955bb9c1c21ac17_EarningsPerShareEarningsPerShareReconciliationDetails"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EarningsPerShareAntidilutivesharesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#EarningsPerShareAntidilutivesharesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EarningsPerShareAntidilutivesharesDetails" xlink:type="extended" id="i49bde85b521246a2a7102bfec8282904_EarningsPerShareAntidilutivesharesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_64698932-7eeb-4bab-8cf0-e37fc2fb721a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_411877f0-3fed-4a54-a510-9ce9c4752298" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_64698932-7eeb-4bab-8cf0-e37fc2fb721a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_411877f0-3fed-4a54-a510-9ce9c4752298" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_0fcc9a66-50bb-4dc0-ac2a-374a641bc642" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_64698932-7eeb-4bab-8cf0-e37fc2fb721a" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_0fcc9a66-50bb-4dc0-ac2a-374a641bc642" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a17f052b-77f0-47a9-9b95-deea7fe87803" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_0fcc9a66-50bb-4dc0-ac2a-374a641bc642" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a17f052b-77f0-47a9-9b95-deea7fe87803" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a17f052b-77f0-47a9-9b95-deea7fe87803_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a17f052b-77f0-47a9-9b95-deea7fe87803" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_a17f052b-77f0-47a9-9b95-deea7fe87803_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_17baf67c-ac26-46da-a0ee-fa7a1f21c22a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_a17f052b-77f0-47a9-9b95-deea7fe87803" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_17baf67c-ac26-46da-a0ee-fa7a1f21c22a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_f77c7eee-0c51-4525-b2a3-f7228c0dcf41" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockCompensationPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_17baf67c-ac26-46da-a0ee-fa7a1f21c22a" xlink:to="loc_us-gaap_StockCompensationPlanMember_f77c7eee-0c51-4525-b2a3-f7228c0dcf41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_c111f9e8-1320-461c-be89-833982a32e59" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_17baf67c-ac26-46da-a0ee-fa7a1f21c22a" xlink:to="loc_us-gaap_RestrictedStockMember_c111f9e8-1320-461c-be89-833982a32e59" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivatives" xlink:type="simple" xlink:href="bkh-20210331.xsd#RiskManagementandDerivatives"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivatives" xlink:type="extended" id="i6d93d2a17b304b6089f45b2adde472e3_RiskManagementandDerivatives"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#RiskManagementandDerivativesTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesTables" xlink:type="extended" id="i0e16e3cb986745089708ff4ae7366319_RiskManagementandDerivativesTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesUtilitiesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RiskManagementandDerivativesUtilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesUtilitiesDetails" xlink:type="extended" id="i3b10e87f2b8049d6929fc0444fd3143c_RiskManagementandDerivativesUtilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_71191d2f-bedc-4f4b-bb68-aa0abb4b1807" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNonmonetaryNotionalAmount_e0c04720-0022-4121-b9fc-f72cca53fac0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeNonmonetaryNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_71191d2f-bedc-4f4b-bb68-aa0abb4b1807" xlink:to="loc_us-gaap_DerivativeNonmonetaryNotionalAmount_e0c04720-0022-4121-b9fc-f72cca53fac0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeRemainingMaturity1_65795000-2662-4e79-8e13-8d06274c3acd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeRemainingMaturity1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_71191d2f-bedc-4f4b-bb68-aa0abb4b1807" xlink:to="loc_us-gaap_DerivativeRemainingMaturity1_65795000-2662-4e79-8e13-8d06274c3acd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollateralAlreadyPostedAggregateFairValue_ca8130dd-fc3e-4a52-a49c-c09def6e66b7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralAlreadyPostedAggregateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_71191d2f-bedc-4f4b-bb68-aa0abb4b1807" xlink:to="loc_us-gaap_CollateralAlreadyPostedAggregateFairValue_ca8130dd-fc3e-4a52-a49c-c09def6e66b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_bf6524e6-fffb-4b05-ba27-5f14453ca5b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_71191d2f-bedc-4f4b-bb68-aa0abb4b1807" xlink:to="loc_us-gaap_DerivativeTable_bf6524e6-fffb-4b05-ba27-5f14453ca5b1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyAxis_2d0a945d-eee8-47c7-8b64-a9c73b9caa2e" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_bf6524e6-fffb-4b05-ba27-5f14453ca5b1" xlink:to="loc_srt_EnergyAxis_2d0a945d-eee8-47c7-8b64-a9c73b9caa2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_2d0a945d-eee8-47c7-8b64-a9c73b9caa2e_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_EnergyAxis_2d0a945d-eee8-47c7-8b64-a9c73b9caa2e" xlink:to="loc_srt_EnergyDomain_2d0a945d-eee8-47c7-8b64-a9c73b9caa2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_269fe660-09be-42ca-b498-636b4dd39855" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_EnergyAxis_2d0a945d-eee8-47c7-8b64-a9c73b9caa2e" xlink:to="loc_srt_EnergyDomain_269fe660-09be-42ca-b498-636b4dd39855" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasDistributionMember_81a0ac0b-5516-4b16-b63e-7bd5f36b947a" xlink:href="bkh-20210331.xsd#bkh_NaturalGasDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_269fe660-09be-42ca-b498-636b4dd39855" xlink:to="loc_bkh_NaturalGasDistributionMember_81a0ac0b-5516-4b16-b63e-7bd5f36b947a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ElectricityMember_8967abb1-6d81-4d18-b9a8-dbb7d84da922" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ElectricityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_269fe660-09be-42ca-b498-636b4dd39855" xlink:to="loc_us-gaap_ElectricityMember_8967abb1-6d81-4d18-b9a8-dbb7d84da922" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_198a1d7c-3f02-46b5-a985-7c7698d4a0eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_bf6524e6-fffb-4b05-ba27-5f14453ca5b1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_198a1d7c-3f02-46b5-a985-7c7698d4a0eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_198a1d7c-3f02-46b5-a985-7c7698d4a0eb_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_198a1d7c-3f02-46b5-a985-7c7698d4a0eb" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_198a1d7c-3f02-46b5-a985-7c7698d4a0eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_198a1d7c-3f02-46b5-a985-7c7698d4a0eb" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FutureMember_1b73b3ba-860b-45f6-9c7f-0587adcbb2ec" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FutureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:to="loc_us-gaap_FutureMember_1b73b3ba-860b-45f6-9c7f-0587adcbb2ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityOptionMember_06f361df-89b3-4c06-acbd-c90b26e0301b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:to="loc_us-gaap_CommodityOptionMember_06f361df-89b3-4c06-acbd-c90b26e0301b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BasisSwapMember_f2924e98-7e21-454f-ae07-467c8f691b53" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BasisSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:to="loc_us-gaap_BasisSwapMember_f2924e98-7e21-454f-ae07-467c8f691b53" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FixedforFloatSwapsPurchasedMember_2eddf4aa-2baf-4bff-94bd-146e79f14e8b" xlink:href="bkh-20210331.xsd#bkh_FixedforFloatSwapsPurchasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:to="loc_bkh_FixedforFloatSwapsPurchasedMember_2eddf4aa-2baf-4bff-94bd-146e79f14e8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasPhysicalPurchasesMember_68771984-e93b-4358-90d5-6a4cbe10582c" xlink:href="bkh-20210331.xsd#bkh_NaturalGasPhysicalPurchasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:to="loc_bkh_NaturalGasPhysicalPurchasesMember_68771984-e93b-4358-90d5-6a4cbe10582c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EnergyRelatedDerivativeMember_9379ebdf-b6c3-4ed3-a9cb-37b52b8a96a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EnergyRelatedDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_252f8d7f-da34-4ebb-8a33-8683505d7ba9" xlink:to="loc_us-gaap_EnergyRelatedDerivativeMember_9379ebdf-b6c3-4ed3-a9cb-37b52b8a96a9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_5ab21c89-fa09-448a-a0a2-b21aab8137a0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_bf6524e6-fffb-4b05-ba27-5f14453ca5b1" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_5ab21c89-fa09-448a-a0a2-b21aab8137a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_5ab21c89-fa09-448a-a0a2-b21aab8137a0_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_5ab21c89-fa09-448a-a0a2-b21aab8137a0" xlink:to="loc_us-gaap_HedgingRelationshipDomain_5ab21c89-fa09-448a-a0a2-b21aab8137a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_31324296-283b-4dbe-81ea-b996dbc72069" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_5ab21c89-fa09-448a-a0a2-b21aab8137a0" xlink:to="loc_us-gaap_HedgingRelationshipDomain_31324296-283b-4dbe-81ea-b996dbc72069" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_26da5d66-1f2c-4e76-b33d-cf6118f36e4d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_31324296-283b-4dbe-81ea-b996dbc72069" xlink:to="loc_us-gaap_CashFlowHedgingMember_26da5d66-1f2c-4e76-b33d-cf6118f36e4d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails" xlink:type="extended" id="i620167d580154b5ca3aaa6ac671977a8_RiskManagementandDerivativesDerivativesbyBalanceSheetClassificationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_b10d3326-63c0-41ba-a989-56bbb3e6c161" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgeAssetsAtFairValue_eac8f56d-fb15-47c4-9abc-d802d14e51c3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueHedgeAssetsAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_b10d3326-63c0-41ba-a989-56bbb3e6c161" xlink:to="loc_us-gaap_FairValueHedgeAssetsAtFairValue_eac8f56d-fb15-47c4-9abc-d802d14e51c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgeLiabilitiesAtFairValue_2a122ec9-5657-4e6f-8c9c-729d8007095c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueHedgeLiabilitiesAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_b10d3326-63c0-41ba-a989-56bbb3e6c161" xlink:to="loc_us-gaap_FairValueHedgeLiabilitiesAtFairValue_2a122ec9-5657-4e6f-8c9c-729d8007095c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueHedgesAtFairValueNet_bb764027-380f-4cfb-9678-32ba73f3d4ed" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueHedgesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_b10d3326-63c0-41ba-a989-56bbb3e6c161" xlink:to="loc_us-gaap_FairValueHedgesAtFairValueNet_bb764027-380f-4cfb-9678-32ba73f3d4ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_30e3cfe6-f464-4585-ba26-b6df68b00522" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_b10d3326-63c0-41ba-a989-56bbb3e6c161" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_30e3cfe6-f464-4585-ba26-b6df68b00522" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_6c2e7a36-f205-4192-b235-bff4b60b6b48" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_30e3cfe6-f464-4585-ba26-b6df68b00522" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_6c2e7a36-f205-4192-b235-bff4b60b6b48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_6c2e7a36-f205-4192-b235-bff4b60b6b48_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_6c2e7a36-f205-4192-b235-bff4b60b6b48" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_6c2e7a36-f205-4192-b235-bff4b60b6b48_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1e067343-e106-4373-9463-3ca128ae5664" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_6c2e7a36-f205-4192-b235-bff4b60b6b48" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1e067343-e106-4373-9463-3ca128ae5664" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_e645761b-baf2-43ac-9120-4d10ba9351b1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1e067343-e106-4373-9463-3ca128ae5664" xlink:to="loc_us-gaap_CommodityContractMember_e645761b-baf2-43ac-9120-4d10ba9351b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_47878106-4a9d-472f-8162-8733d2827f1a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_30e3cfe6-f464-4585-ba26-b6df68b00522" xlink:to="loc_us-gaap_HedgingDesignationAxis_47878106-4a9d-472f-8162-8733d2827f1a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_47878106-4a9d-472f-8162-8733d2827f1a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_47878106-4a9d-472f-8162-8733d2827f1a" xlink:to="loc_us-gaap_HedgingDesignationDomain_47878106-4a9d-472f-8162-8733d2827f1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_888072ea-7746-4ca2-9aaf-2a293d7c26f2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_47878106-4a9d-472f-8162-8733d2827f1a" xlink:to="loc_us-gaap_HedgingDesignationDomain_888072ea-7746-4ca2-9aaf-2a293d7c26f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_d770c349-fb7b-4e36-a0e7-8994038ec51a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_888072ea-7746-4ca2-9aaf-2a293d7c26f2" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_d770c349-fb7b-4e36-a0e7-8994038ec51a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_7520921f-755e-44fe-93ce-45b1ed74788d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_888072ea-7746-4ca2-9aaf-2a293d7c26f2" xlink:to="loc_us-gaap_NondesignatedMember_7520921f-755e-44fe-93ce-45b1ed74788d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_76f564a3-b502-4735-adf4-83453f6e6618" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_30e3cfe6-f464-4585-ba26-b6df68b00522" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_76f564a3-b502-4735-adf4-83453f6e6618" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_76f564a3-b502-4735-adf4-83453f6e6618_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_76f564a3-b502-4735-adf4-83453f6e6618" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_76f564a3-b502-4735-adf4-83453f6e6618_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_4db48e54-3b41-44f5-9485-0b8b44c7966c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_76f564a3-b502-4735-adf4-83453f6e6618" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_4db48e54-3b41-44f5-9485-0b8b44c7966c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeAssetsCurrentMember_c08edd0f-bb4c-4f0b-a7dc-0c1e10e2665d" xlink:href="bkh-20210331.xsd#bkh_DerivativeAssetsCurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_4db48e54-3b41-44f5-9485-0b8b44c7966c" xlink:to="loc_bkh_DerivativeAssetsCurrentMember_c08edd0f-bb4c-4f0b-a7dc-0c1e10e2665d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeAssetsNoncurrentMember_1c020d7f-e24b-4489-8c51-074b654ab3d7" xlink:href="bkh-20210331.xsd#bkh_DerivativeAssetsNoncurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_4db48e54-3b41-44f5-9485-0b8b44c7966c" xlink:to="loc_bkh_DerivativeAssetsNoncurrentMember_1c020d7f-e24b-4489-8c51-074b654ab3d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeLiabilitiesCurrentMember_2786c40d-0afc-4074-9b60-5ad99227eb34" xlink:href="bkh-20210331.xsd#bkh_DerivativeLiabilitiesCurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_4db48e54-3b41-44f5-9485-0b8b44c7966c" xlink:to="loc_bkh_DerivativeLiabilitiesCurrentMember_2786c40d-0afc-4074-9b60-5ad99227eb34" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_DerivativeLiabilitiesNoncurrentMember_1a02d747-5939-47e5-b3ea-b0777623fe76" xlink:href="bkh-20210331.xsd#bkh_DerivativeLiabilitiesNoncurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_4db48e54-3b41-44f5-9485-0b8b44c7966c" xlink:to="loc_bkh_DerivativeLiabilitiesNoncurrentMember_1a02d747-5939-47e5-b3ea-b0777623fe76" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails" xlink:type="extended" id="i9ab86a959c774494a133002edf77455e_RiskManagementandDerivativesDerivativesDesignatedasHedgeInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_d75296e2-3213-40c8-a7dd-9eed301cb51d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_ccf3c07b-fcba-497e-b682-09fcda05ce9e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_d75296e2-3213-40c8-a7dd-9eed301cb51d" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_ccf3c07b-fcba-497e-b682-09fcda05ce9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_a2e9eeff-0d17-41fc-ba42-564943f19e19" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_d75296e2-3213-40c8-a7dd-9eed301cb51d" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_a2e9eeff-0d17-41fc-ba42-564943f19e19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_e8807a62-056a-4fdf-acc5-72beef12929d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_d75296e2-3213-40c8-a7dd-9eed301cb51d" xlink:to="loc_us-gaap_DerivativeTable_e8807a62-056a-4fdf-acc5-72beef12929d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_e08b629e-5424-436d-840c-510ee9147609" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_e8807a62-056a-4fdf-acc5-72beef12929d" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_e08b629e-5424-436d-840c-510ee9147609" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_e08b629e-5424-436d-840c-510ee9147609_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_e08b629e-5424-436d-840c-510ee9147609" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_e08b629e-5424-436d-840c-510ee9147609_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9f1ce7c5-5a1b-4e39-aa5a-7957bd99bca0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_e08b629e-5424-436d-840c-510ee9147609" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9f1ce7c5-5a1b-4e39-aa5a-7957bd99bca0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_b95e7d5b-5da3-4bc4-8315-e12fb3c89797" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9f1ce7c5-5a1b-4e39-aa5a-7957bd99bca0" xlink:to="loc_us-gaap_InterestExpenseMember_b95e7d5b-5da3-4bc4-8315-e12fb3c89797" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_55a43974-4c92-4757-a55a-8e7979addc12" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9f1ce7c5-5a1b-4e39-aa5a-7957bd99bca0" xlink:to="loc_us-gaap_CostOfSalesMember_55a43974-4c92-4757-a55a-8e7979addc12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_f1f28a51-4274-41a5-b6f0-f5138a997fd7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_e8807a62-056a-4fdf-acc5-72beef12929d" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_f1f28a51-4274-41a5-b6f0-f5138a997fd7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_f1f28a51-4274-41a5-b6f0-f5138a997fd7_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_f1f28a51-4274-41a5-b6f0-f5138a997fd7" xlink:to="loc_us-gaap_HedgingRelationshipDomain_f1f28a51-4274-41a5-b6f0-f5138a997fd7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_b09c23f8-03cb-4452-853c-d3148e37f410" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_f1f28a51-4274-41a5-b6f0-f5138a997fd7" xlink:to="loc_us-gaap_HedgingRelationshipDomain_b09c23f8-03cb-4452-853c-d3148e37f410" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_3d63ec8e-cbe1-44cc-a113-6dba1287607e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_b09c23f8-03cb-4452-853c-d3148e37f410" xlink:to="loc_us-gaap_CashFlowHedgingMember_3d63ec8e-cbe1-44cc-a113-6dba1287607e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_80d5e488-5eb0-4e7c-ae53-ef5078bdf344" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_e8807a62-056a-4fdf-acc5-72beef12929d" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_80d5e488-5eb0-4e7c-ae53-ef5078bdf344" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_80d5e488-5eb0-4e7c-ae53-ef5078bdf344_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_80d5e488-5eb0-4e7c-ae53-ef5078bdf344" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_80d5e488-5eb0-4e7c-ae53-ef5078bdf344_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_2bbef5ce-7906-4abe-a8bc-225fc95a56c3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_80d5e488-5eb0-4e7c-ae53-ef5078bdf344" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_2bbef5ce-7906-4abe-a8bc-225fc95a56c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasDistributionMember_3f33246a-00ca-4c46-bf91-edf8129773a1" xlink:href="bkh-20210331.xsd#bkh_NaturalGasDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2bbef5ce-7906-4abe-a8bc-225fc95a56c3" xlink:to="loc_bkh_NaturalGasDistributionMember_3f33246a-00ca-4c46-bf91-edf8129773a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_ce5dfd83-55d6-47dd-84db-30cb5376ef19" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2bbef5ce-7906-4abe-a8bc-225fc95a56c3" xlink:to="loc_us-gaap_InterestRateSwapMember_ce5dfd83-55d6-47dd-84db-30cb5376ef19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_69185309-7109-451e-95b9-bc018068298f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2bbef5ce-7906-4abe-a8bc-225fc95a56c3" xlink:to="loc_us-gaap_CommodityContractMember_69185309-7109-451e-95b9-bc018068298f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_InterestRateSwapAndCommodityDerivativeMember_704d2485-efe6-4832-8957-5c35c32149d8" xlink:href="bkh-20210331.xsd#bkh_InterestRateSwapAndCommodityDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_2bbef5ce-7906-4abe-a8bc-225fc95a56c3" xlink:to="loc_bkh_InterestRateSwapAndCommodityDerivativeMember_704d2485-efe6-4832-8957-5c35c32149d8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_abdf9f6e-cb6e-4da7-b608-9160503fb221" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_e8807a62-056a-4fdf-acc5-72beef12929d" xlink:to="loc_us-gaap_HedgingDesignationAxis_abdf9f6e-cb6e-4da7-b608-9160503fb221" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_abdf9f6e-cb6e-4da7-b608-9160503fb221_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_abdf9f6e-cb6e-4da7-b608-9160503fb221" xlink:to="loc_us-gaap_HedgingDesignationDomain_abdf9f6e-cb6e-4da7-b608-9160503fb221_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_683d51de-8cd9-42e4-9833-26c40ae7db76" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_abdf9f6e-cb6e-4da7-b608-9160503fb221" xlink:to="loc_us-gaap_HedgingDesignationDomain_683d51de-8cd9-42e4-9833-26c40ae7db76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_3d3cf200-9016-4cbf-b601-669e5d6c76ab" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_683d51de-8cd9-42e4-9833-26c40ae7db76" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_3d3cf200-9016-4cbf-b601-669e5d6c76ab" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails" xlink:type="extended" id="ief51cadc81244914861affadc3f9d480_RiskManagementandDerivativesDerivativesNotDesignatedasHedgeInstrumentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_3c08c9c0-504c-47a1-a9ee-1b0055ba9ab6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_397adb26-3eae-4c82-aeee-fd300e3e85d2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3c08c9c0-504c-47a1-a9ee-1b0055ba9ab6" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_397adb26-3eae-4c82-aeee-fd300e3e85d2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_aabef700-0adb-492a-a297-2c191c2627a2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_3c08c9c0-504c-47a1-a9ee-1b0055ba9ab6" xlink:to="loc_us-gaap_RegulatoryAssets_aabef700-0adb-492a-a297-2c191c2627a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_57955cd0-fe50-452c-95fd-fb32429b47af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_3c08c9c0-504c-47a1-a9ee-1b0055ba9ab6" xlink:to="loc_us-gaap_DerivativeTable_57955cd0-fe50-452c-95fd-fb32429b47af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_1869e179-16a8-4370-b5fe-8cd8980a747d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_57955cd0-fe50-452c-95fd-fb32429b47af" xlink:to="loc_us-gaap_HedgingDesignationAxis_1869e179-16a8-4370-b5fe-8cd8980a747d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_1869e179-16a8-4370-b5fe-8cd8980a747d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_1869e179-16a8-4370-b5fe-8cd8980a747d" xlink:to="loc_us-gaap_HedgingDesignationDomain_1869e179-16a8-4370-b5fe-8cd8980a747d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_c6e2bc7c-441d-4307-8a4a-b4723ac6dfbc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_1869e179-16a8-4370-b5fe-8cd8980a747d" xlink:to="loc_us-gaap_HedgingDesignationDomain_c6e2bc7c-441d-4307-8a4a-b4723ac6dfbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_11950465-f6a1-4f4a-b8e1-aba4b9ee3424" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_c6e2bc7c-441d-4307-8a4a-b4723ac6dfbc" xlink:to="loc_us-gaap_NondesignatedMember_11950465-f6a1-4f4a-b8e1-aba4b9ee3424" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_58d7bb90-548d-4b06-b055-e68241bfbabe" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_57955cd0-fe50-452c-95fd-fb32429b47af" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_58d7bb90-548d-4b06-b055-e68241bfbabe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_58d7bb90-548d-4b06-b055-e68241bfbabe_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_58d7bb90-548d-4b06-b055-e68241bfbabe" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_58d7bb90-548d-4b06-b055-e68241bfbabe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_cf9ccbb8-25a7-494a-bdb0-4e06da15b3e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_58d7bb90-548d-4b06-b055-e68241bfbabe" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_cf9ccbb8-25a7-494a-bdb0-4e06da15b3e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_76f66799-a506-4be9-aed8-47aedd435241" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_cf9ccbb8-25a7-494a-bdb0-4e06da15b3e9" xlink:to="loc_us-gaap_CostOfSalesMember_76f66799-a506-4be9-aed8-47aedd435241" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyAxis_741c66a3-ceed-4b22-bae4-0f2b015b1c43" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_57955cd0-fe50-452c-95fd-fb32429b47af" xlink:to="loc_srt_EnergyAxis_741c66a3-ceed-4b22-bae4-0f2b015b1c43" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_741c66a3-ceed-4b22-bae4-0f2b015b1c43_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_EnergyAxis_741c66a3-ceed-4b22-bae4-0f2b015b1c43" xlink:to="loc_srt_EnergyDomain_741c66a3-ceed-4b22-bae4-0f2b015b1c43_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EnergyDomain_9829c31b-e16f-4068-9a96-5b3e7e940263" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EnergyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_EnergyAxis_741c66a3-ceed-4b22-bae4-0f2b015b1c43" xlink:to="loc_srt_EnergyDomain_9829c31b-e16f-4068-9a96-5b3e7e940263" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ElectricityMember_a6027785-6a01-4e0d-be67-9139748cd939" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ElectricityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_9829c31b-e16f-4068-9a96-5b3e7e940263" xlink:to="loc_us-gaap_ElectricityMember_a6027785-6a01-4e0d-be67-9139748cd939" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_NaturalGasDistributionMember_e0e6e9eb-b7cb-41a3-9050-88ee610e3ebe" xlink:href="bkh-20210331.xsd#bkh_NaturalGasDistributionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EnergyDomain_9829c31b-e16f-4068-9a96-5b3e7e940263" xlink:to="loc_bkh_NaturalGasDistributionMember_e0e6e9eb-b7cb-41a3-9050-88ee610e3ebe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetAxis_bbb5034f-b6da-427b-a8af-3f39edcf5592" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_57955cd0-fe50-452c-95fd-fb32429b47af" xlink:to="loc_us-gaap_RegulatoryAssetAxis_bbb5034f-b6da-427b-a8af-3f39edcf5592" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_bbb5034f-b6da-427b-a8af-3f39edcf5592_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RegulatoryAssetAxis_bbb5034f-b6da-427b-a8af-3f39edcf5592" xlink:to="loc_us-gaap_RegulatoryAssetDomain_bbb5034f-b6da-427b-a8af-3f39edcf5592_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssetDomain_bb759a3b-8337-4b6a-afb3-225169fb30a9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssetDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RegulatoryAssetAxis_bbb5034f-b6da-427b-a8af-3f39edcf5592" xlink:to="loc_us-gaap_RegulatoryAssetDomain_bb759a3b-8337-4b6a-afb3-225169fb30a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PriceRiskDerivativeMember_b5a08571-d1c1-4468-a5a8-81a004be34f6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PriceRiskDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RegulatoryAssetDomain_bb759a3b-8337-4b6a-afb3-225169fb30a9" xlink:to="loc_us-gaap_PriceRiskDerivativeMember_b5a08571-d1c1-4468-a5a8-81a004be34f6" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FairValueMeasurements" xlink:type="simple" xlink:href="bkh-20210331.xsd#FairValueMeasurements"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FairValueMeasurements" xlink:type="extended" id="idae3bf2c9bf0473990716f0bf5aa5699_FairValueMeasurements"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FairValueMeasurementsTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#FairValueMeasurementsTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FairValueMeasurementsTables" xlink:type="extended" id="i835bf3b5cab34034853c3d2b31530b29_FairValueMeasurementsTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FairValueMeasurementsScheduleofFairValuesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#FairValueMeasurementsScheduleofFairValuesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FairValueMeasurementsScheduleofFairValuesDetails" xlink:type="extended" id="i5f168b43f25248c68870b95e62ac997e_FairValueMeasurementsScheduleofFairValuesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_7edee681-02d7-4b6d-9d12-a372906a6327" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_DerivativeAssets_7edee681-02d7-4b6d-9d12-a372906a6327" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset_6c0b10bd-9032-48bb-96cb-bb289e34de80" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_DerivativeAssetFairValueGrossLiabilityAndObligationToReturnCashOffset_6c0b10bd-9032-48bb-96cb-bb289e34de80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_725d2e3b-2887-44b9-805e-3307cd66aad4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_725d2e3b-2887-44b9-805e-3307cd66aad4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_a5a633ad-71bf-4ea2-a257-5bbf62ec9e3e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_DerivativeLiabilities_a5a633ad-71bf-4ea2-a257-5bbf62ec9e3e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset_fd16a423-0cb6-4b5d-bac7-8f46e086fb9f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_DerivativeLiabilityFairValueGrossAssetAndRightToReclaimCashOffset_fd16a423-0cb6-4b5d-bac7-8f46e086fb9f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_ef270287-ed8c-48d4-9695-cc7092de786d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_ef270287-ed8c-48d4-9695-cc7092de786d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_a60fce3a-2714-4e32-a70b-3ce449aca8d6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_6f8d6da9-4831-428a-a638-857c7af80b67" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_a60fce3a-2714-4e32-a70b-3ce449aca8d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_c1446d2d-d081-4bf4-8336-cbc7cfdfb5b4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_a60fce3a-2714-4e32-a70b-3ce449aca8d6" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_c1446d2d-d081-4bf4-8336-cbc7cfdfb5b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c1446d2d-d081-4bf4-8336-cbc7cfdfb5b4_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c1446d2d-d081-4bf4-8336-cbc7cfdfb5b4" xlink:to="loc_us-gaap_SegmentDomain_c1446d2d-d081-4bf4-8336-cbc7cfdfb5b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a75cec6c-4d9b-4239-ba40-f1361e4b95d1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c1446d2d-d081-4bf4-8336-cbc7cfdfb5b4" xlink:to="loc_us-gaap_SegmentDomain_a75cec6c-4d9b-4239-ba40-f1361e4b95d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_0c36578d-b1dc-40f8-b4e6-20ab347ff964" xlink:href="bkh-20210331.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a75cec6c-4d9b-4239-ba40-f1361e4b95d1" xlink:to="loc_bkh_GasUtilitiesMember_0c36578d-b1dc-40f8-b4e6-20ab347ff964" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_d8ff0076-f5d3-455a-88e7-0c1117c308c4" xlink:href="bkh-20210331.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a75cec6c-4d9b-4239-ba40-f1361e4b95d1" xlink:to="loc_bkh_ElectricUtilitiesMember_d8ff0076-f5d3-455a-88e7-0c1117c308c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27be9993-fe70-42fa-969a-915f06999139" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_a60fce3a-2714-4e32-a70b-3ce449aca8d6" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27be9993-fe70-42fa-969a-915f06999139" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_27be9993-fe70-42fa-969a-915f06999139_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27be9993-fe70-42fa-969a-915f06999139" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_27be9993-fe70-42fa-969a-915f06999139_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_59d1a6ad-c611-49c8-8ae3-9f89918f0513" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_27be9993-fe70-42fa-969a-915f06999139" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_59d1a6ad-c611-49c8-8ae3-9f89918f0513" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_253eed8e-ac80-4e3f-952b-15ca88f91bee" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_59d1a6ad-c611-49c8-8ae3-9f89918f0513" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_253eed8e-ac80-4e3f-952b-15ca88f91bee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0e24bc4-c462-4013-ab57-c8ad24c2876d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_a60fce3a-2714-4e32-a70b-3ce449aca8d6" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0e24bc4-c462-4013-ab57-c8ad24c2876d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0e24bc4-c462-4013-ab57-c8ad24c2876d_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0e24bc4-c462-4013-ab57-c8ad24c2876d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c0e24bc4-c462-4013-ab57-c8ad24c2876d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8e0d488-270f-48ba-ad02-142346e0f947" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_c0e24bc4-c462-4013-ab57-c8ad24c2876d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8e0d488-270f-48ba-ad02-142346e0f947" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_5491021c-2d6b-4569-af2b-511994c36555" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8e0d488-270f-48ba-ad02-142346e0f947" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_5491021c-2d6b-4569-af2b-511994c36555" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_32fd5f12-feda-40ea-bdad-e87cb1afc714" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8e0d488-270f-48ba-ad02-142346e0f947" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_32fd5f12-feda-40ea-bdad-e87cb1afc714" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_70ec70b0-3183-48da-8a6b-92e6d8ba4900" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c8e0d488-270f-48ba-ad02-142346e0f947" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_70ec70b0-3183-48da-8a6b-92e6d8ba4900" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_b4663fef-71e3-4626-9186-e97ff8a39d2e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_a60fce3a-2714-4e32-a70b-3ce449aca8d6" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_b4663fef-71e3-4626-9186-e97ff8a39d2e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_b4663fef-71e3-4626-9186-e97ff8a39d2e_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_b4663fef-71e3-4626-9186-e97ff8a39d2e" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_b4663fef-71e3-4626-9186-e97ff8a39d2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_7f3403e6-29c5-4bc7-97aa-21d92515e0ba" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_b4663fef-71e3-4626-9186-e97ff8a39d2e" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_7f3403e6-29c5-4bc7-97aa-21d92515e0ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_06ec11b9-b350-4eb3-a5fa-b72f4c5fd717" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_7f3403e6-29c5-4bc7-97aa-21d92515e0ba" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_06ec11b9-b350-4eb3-a5fa-b72f4c5fd717" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_8900683e-62c9-4146-a2b1-017f03a44683" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_06ec11b9-b350-4eb3-a5fa-b72f4c5fd717" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_8900683e-62c9-4146-a2b1-017f03a44683" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/FairValueMeasurementsOtherFairValueMeasurementsDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#FairValueMeasurementsOtherFairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/FairValueMeasurementsOtherFairValueMeasurementsDetails" xlink:type="extended" id="i9b7c3d99b37a47d9aab6411dbbcbf587_FairValueMeasurementsOtherFairValueMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9ceab58c-d92f-4ec9-ae2e-ac7627019fdc" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_1acd8713-7674-4d46-9865-686eb33360e4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9ceab58c-d92f-4ec9-ae2e-ac7627019fdc" xlink:to="loc_us-gaap_LongTermDebt_1acd8713-7674-4d46-9865-686eb33360e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_28923d79-7b00-477c-9978-094f32615c89" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9ceab58c-d92f-4ec9-ae2e-ac7627019fdc" xlink:to="loc_us-gaap_LongTermDebtFairValue_28923d79-7b00-477c-9978-094f32615c89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_ba4f4dd5-dbc7-4d2d-828f-bd9a7ab8d732" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9ceab58c-d92f-4ec9-ae2e-ac7627019fdc" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_ba4f4dd5-dbc7-4d2d-828f-bd9a7ab8d732" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_007bf9a6-404f-447a-ab25-452295a48e8a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_ba4f4dd5-dbc7-4d2d-828f-bd9a7ab8d732" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_007bf9a6-404f-447a-ab25-452295a48e8a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_007bf9a6-404f-447a-ab25-452295a48e8a_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_007bf9a6-404f-447a-ab25-452295a48e8a" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_007bf9a6-404f-447a-ab25-452295a48e8a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_81c8ff71-1a8e-4a0e-a4c2-d89c4ed3880d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_007bf9a6-404f-447a-ab25-452295a48e8a" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_81c8ff71-1a8e-4a0e-a4c2-d89c4ed3880d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_1082cbee-0962-4a1a-abe4-0a459d75bd46" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_81c8ff71-1a8e-4a0e-a4c2-d89c4ed3880d" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_1082cbee-0962-4a1a-abe4-0a459d75bd46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_3a0f70a7-a8f8-4749-9feb-9b1ea0737627" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_1082cbee-0962-4a1a-abe4-0a459d75bd46" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_3a0f70a7-a8f8-4749-9feb-9b1ea0737627" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_8f274124-888d-4f0a-8fee-5d98e69e2411" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_1082cbee-0962-4a1a-abe4-0a459d75bd46" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_8f274124-888d-4f0a-8fee-5d98e69e2411" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/OtherComprehensiveIncome" xlink:type="simple" xlink:href="bkh-20210331.xsd#OtherComprehensiveIncome"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/OtherComprehensiveIncome" xlink:type="extended" id="i48044c6395784cee8e8b54fd77a8c539_OtherComprehensiveIncome"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#OtherComprehensiveIncomeTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeTables" xlink:type="extended" id="i3d746ff350e24350ba4609cce0798337_OtherComprehensiveIncomeTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails" xlink:type="extended" id="i24b61ea867384ae3a217968a60326ec2_OtherComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeLossDetails">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedStatementOfIncomeCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsIncurred_78788755-d51d-46bf-954e-3dcc4664488f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestCostsIncurred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_us-gaap_InterestCostsIncurred_78788755-d51d-46bf-954e-3dcc4664488f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_FuelPurchasedPowerAndCostOfGasSold_ec0f2eca-7dfb-4dba-90db-b353968b04f6" xlink:href="bkh-20210331.xsd#bkh_FuelPurchasedPowerAndCostOfGasSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_bkh_FuelPurchasedPowerAndCostOfGasSold_ec0f2eca-7dfb-4dba-90db-b353968b04f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OperatingExpenseMaintenanceOperationsandOtherCostsandExpense_1f474896-41e7-42db-95df-e3198dbdaf86" xlink:href="bkh-20210331.xsd#bkh_OperatingExpenseMaintenanceOperationsandOtherCostsandExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_bkh_OperatingExpenseMaintenanceOperationsandOtherCostsandExpense_1f474896-41e7-42db-95df-e3198dbdaf86" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_6079ea43-fd14-4619-87ae-c7f79a63cb23" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_6079ea43-fd14-4619-87ae-c7f79a63cb23" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_43c760d0-f128-4ed5-a548-d2c9438cefa4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_43c760d0-f128-4ed5-a548-d2c9438cefa4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_9d2c83b7-2af1-43e7-aa36-3b993f16fc1b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_us-gaap_ProfitLoss_9d2c83b7-2af1-43e7-aa36-3b993f16fc1b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedStatementOfComprehensiveIncomeTable_b1e7b6b1-f795-4bde-8010-8ad46262d4f9" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_CondensedStatementOfComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedStatementOfIncomeCaptionsLineItems_028cef69-0e17-4a40-a871-73455e727d33" xlink:to="loc_srt_CondensedStatementOfComprehensiveIncomeTable_b1e7b6b1-f795-4bde-8010-8ad46262d4f9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_876adb45-f94d-42d9-b979-a17995eaa021" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedStatementOfComprehensiveIncomeTable_b1e7b6b1-f795-4bde-8010-8ad46262d4f9" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_876adb45-f94d-42d9-b979-a17995eaa021" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_876adb45-f94d-42d9-b979-a17995eaa021_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_876adb45-f94d-42d9-b979-a17995eaa021" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_876adb45-f94d-42d9-b979-a17995eaa021_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5c2d56c6-9cef-48da-8413-20b31992e1c1" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_876adb45-f94d-42d9-b979-a17995eaa021" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5c2d56c6-9cef-48da-8413-20b31992e1c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_820ce452-e941-4d87-b342-c5d79425a7a7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5c2d56c6-9cef-48da-8413-20b31992e1c1" xlink:to="loc_us-gaap_InterestRateSwapMember_820ce452-e941-4d87-b342-c5d79425a7a7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_9ffbcb1d-c7d1-47a7-b089-ece8fdc97413" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_5c2d56c6-9cef-48da-8413-20b31992e1c1" xlink:to="loc_us-gaap_CommodityContractMember_9ffbcb1d-c7d1-47a7-b089-ece8fdc97413" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_39920589-cb97-431e-ac01-5237db260d43" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedStatementOfComprehensiveIncomeTable_b1e7b6b1-f795-4bde-8010-8ad46262d4f9" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_39920589-cb97-431e-ac01-5237db260d43" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_39920589-cb97-431e-ac01-5237db260d43_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_39920589-cb97-431e-ac01-5237db260d43" xlink:to="loc_us-gaap_EquityComponentDomain_39920589-cb97-431e-ac01-5237db260d43_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c1a4423b-a59a-45ac-9344-3f37733bf272" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_39920589-cb97-431e-ac01-5237db260d43" xlink:to="loc_us-gaap_EquityComponentDomain_c1a4423b-a59a-45ac-9344-3f37733bf272" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_ad165df7-b9b2-4e91-8c36-cd685e7e6a36" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c1a4423b-a59a-45ac-9344-3f37733bf272" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_ad165df7-b9b2-4e91-8c36-cd685e7e6a36" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_f6b56407-7667-4a7c-a342-856436c66b0b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c1a4423b-a59a-45ac-9344-3f37733bf272" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_f6b56407-7667-4a7c-a342-856436c66b0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_91079b1f-f893-497a-8b7b-a9afa4034ef8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c1a4423b-a59a-45ac-9344-3f37733bf272" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember_91079b1f-f893-497a-8b7b-a9afa4034ef8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_49b76eab-9633-4b4d-b2ee-141d67dc5cff" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c1a4423b-a59a-45ac-9344-3f37733bf272" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_49b76eab-9633-4b4d-b2ee-141d67dc5cff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_91cba791-0a10-49db-89fe-2cfe2c1adb41" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedStatementOfComprehensiveIncomeTable_b1e7b6b1-f795-4bde-8010-8ad46262d4f9" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_91cba791-0a10-49db-89fe-2cfe2c1adb41" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_91cba791-0a10-49db-89fe-2cfe2c1adb41_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_91cba791-0a10-49db-89fe-2cfe2c1adb41" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_91cba791-0a10-49db-89fe-2cfe2c1adb41_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_65acee0e-7407-4eb3-95c3-12adf517d2e8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_91cba791-0a10-49db-89fe-2cfe2c1adb41" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_65acee0e-7407-4eb3-95c3-12adf517d2e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_a0ef0b2e-f109-4436-9514-5f6e28039b72" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_65acee0e-7407-4eb3-95c3-12adf517d2e8" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_a0ef0b2e-f109-4436-9514-5f6e28039b72" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeLossAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#OtherComprehensiveIncomeLossAccumulatedOtherComprehensiveIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/OtherComprehensiveIncomeLossAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended" id="i827535dd5a974e16bf12324786f8703f_OtherComprehensiveIncomeLossAccumulatedOtherComprehensiveIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_618700be-3f22-4734-b9d2-da2373c474e9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_e36261e4-c05f-4754-b2f4-aab99133c9ea" xlink:href="bkh-20210331.xsd#bkh_AccumulatedOtherComprehensiveIncomeRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_618700be-3f22-4734-b9d2-da2373c474e9" xlink:to="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_e36261e4-c05f-4754-b2f4-aab99133c9ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_f797ca30-6b9d-425c-82f1-ae7eaa0698cb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_e36261e4-c05f-4754-b2f4-aab99133c9ea" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_f797ca30-6b9d-425c-82f1-ae7eaa0698cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_94cec942-82b8-4ad8-9fa5-df81d08e9587" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_e36261e4-c05f-4754-b2f4-aab99133c9ea" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_94cec942-82b8-4ad8-9fa5-df81d08e9587" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_e9f47cb5-e036-43ac-b231-4927c496d1a4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bkh_AccumulatedOtherComprehensiveIncomeRollForward_e36261e4-c05f-4754-b2f4-aab99133c9ea" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_e9f47cb5-e036-43ac-b231-4927c496d1a4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_f508d2ae-4f2f-49e8-b407-6ce65aff36c2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_e86c3321-7f49-4cc0-b077-42073642e499" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_618700be-3f22-4734-b9d2-da2373c474e9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_e86c3321-7f49-4cc0-b077-42073642e499" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_2144b652-58e1-4a1a-82b5-30943a6e1d72" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_e86c3321-7f49-4cc0-b077-42073642e499" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_2144b652-58e1-4a1a-82b5-30943a6e1d72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_2144b652-58e1-4a1a-82b5-30943a6e1d72_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2144b652-58e1-4a1a-82b5-30943a6e1d72" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_2144b652-58e1-4a1a-82b5-30943a6e1d72_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_246c7f26-6cbb-4a7c-b904-61a19a2ec65f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2144b652-58e1-4a1a-82b5-30943a6e1d72" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_246c7f26-6cbb-4a7c-b904-61a19a2ec65f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_23d48c3d-4963-452e-93d5-69646f2205a4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_246c7f26-6cbb-4a7c-b904-61a19a2ec65f" xlink:to="loc_us-gaap_InterestRateSwapMember_23d48c3d-4963-452e-93d5-69646f2205a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_b0174f30-b534-4113-9a91-c54f9cc45c9c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_246c7f26-6cbb-4a7c-b904-61a19a2ec65f" xlink:to="loc_us-gaap_CommodityContractMember_b0174f30-b534-4113-9a91-c54f9cc45c9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c466ee3e-9dc2-4540-afd1-fd81f7986de8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_e86c3321-7f49-4cc0-b077-42073642e499" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c466ee3e-9dc2-4540-afd1-fd81f7986de8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c466ee3e-9dc2-4540-afd1-fd81f7986de8_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c466ee3e-9dc2-4540-afd1-fd81f7986de8" xlink:to="loc_us-gaap_EquityComponentDomain_c466ee3e-9dc2-4540-afd1-fd81f7986de8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c8403501-80cd-418d-ba69-ef3c0d25f45f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c466ee3e-9dc2-4540-afd1-fd81f7986de8" xlink:to="loc_us-gaap_EquityComponentDomain_c8403501-80cd-418d-ba69-ef3c0d25f45f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_6a9328d9-e5bc-44ae-992b-0d702223db3f" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c8403501-80cd-418d-ba69-ef3c0d25f45f" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_6a9328d9-e5bc-44ae-992b-0d702223db3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_cf51ad56-006a-4fed-8501-5e3e171e0243" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c8403501-80cd-418d-ba69-ef3c0d25f45f" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_cf51ad56-006a-4fed-8501-5e3e171e0243" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_2ad0d870-f781-4f31-a77f-e69eff52c164" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_c8403501-80cd-418d-ba69-ef3c0d25f45f" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_2ad0d870-f781-4f31-a77f-e69eff52c164" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_a9c8d672-8b7a-418e-ae06-a0a1ff55ede4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_e86c3321-7f49-4cc0-b077-42073642e499" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_a9c8d672-8b7a-418e-ae06-a0a1ff55ede4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_a9c8d672-8b7a-418e-ae06-a0a1ff55ede4_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_a9c8d672-8b7a-418e-ae06-a0a1ff55ede4" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_a9c8d672-8b7a-418e-ae06-a0a1ff55ede4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_ad7074b4-a33b-49b9-8759-63063b3230b3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_a9c8d672-8b7a-418e-ae06-a0a1ff55ede4" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_ad7074b4-a33b-49b9-8759-63063b3230b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_0fa77c69-42ac-4247-815f-75eec76be1ad" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_ad7074b4-a33b-49b9-8759-63063b3230b3" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_0fa77c69-42ac-4247-815f-75eec76be1ad" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EmployeeBenefitPlans" xlink:type="simple" xlink:href="bkh-20210331.xsd#EmployeeBenefitPlans"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EmployeeBenefitPlans" xlink:type="extended" id="if3c9aa2b6f0042969fbbe084aeb51ce5_EmployeeBenefitPlans"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EmployeeBenefitPlansTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#EmployeeBenefitPlansTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EmployeeBenefitPlansTables" xlink:type="extended" id="i419e4a557a8e4daf9328e3d6dd33cf93_EmployeeBenefitPlansTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/EmployeeBenefitPlansDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#EmployeeBenefitPlansDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/EmployeeBenefitPlansDetails" xlink:type="extended" id="i613c1eed28414894b1b503e08afb5991_EmployeeBenefitPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5d9d6324-91a8-465a-be06-f5014d8be11c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5d9d6324-91a8-465a-be06-f5014d8be11c" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanServiceCost_39dc2e8d-bf13-458a-bba3-89422f235429" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:to="loc_us-gaap_DefinedBenefitPlanServiceCost_39dc2e8d-bf13-458a-bba3-89422f235429" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_9a06397f-2967-4dec-8705-00ab1f0492f4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_9a06397f-2967-4dec-8705-00ab1f0492f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_f433ee43-c047-40c3-b5bb-631aa8af761b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_f433ee43-c047-40c3-b5bb-631aa8af761b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_28a00fbd-8598-4ac1-8247-a835ffa1c9ca" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_28a00fbd-8598-4ac1-8247-a835ffa1c9ca" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_e304a9e0-d9f3-4301-81a7-48423f20da5b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_e304a9e0-d9f3-4301-81a7-48423f20da5b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_14b576c5-d31a-4f7a-9e98-98674828faa9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_61f4272b-afd5-4a99-8314-5b4f6e4545f7" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_14b576c5-d31a-4f7a-9e98-98674828faa9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_ca04ffdf-163c-4062-8377-06b888d2ded6" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5d9d6324-91a8-465a-be06-f5014d8be11c" xlink:to="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_ca04ffdf-163c-4062-8377-06b888d2ded6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_b0b9dbd6-ac8e-45c8-9dd3-d32d21822414" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_ca04ffdf-163c-4062-8377-06b888d2ded6" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_b0b9dbd6-ac8e-45c8-9dd3-d32d21822414" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_0f7b59ed-55bc-4f33-932f-cc7ad019d1f3" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_ca04ffdf-163c-4062-8377-06b888d2ded6" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear_0f7b59ed-55bc-4f33-932f-cc7ad019d1f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_8be4292c-e221-47db-8717-509f68c8947c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PensionAndOtherPostretirementBenefitContributionsAbstract_ca04ffdf-163c-4062-8377-06b888d2ded6" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_8be4292c-e221-47db-8717-509f68c8947c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_321c7c90-5dfb-4944-b4e9-ebddd7647d3e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5d9d6324-91a8-465a-be06-f5014d8be11c" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_321c7c90-5dfb-4944-b4e9-ebddd7647d3e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_b2c7247b-6722-41d7-b0c0-9026e34694d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_321c7c90-5dfb-4944-b4e9-ebddd7647d3e" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_b2c7247b-6722-41d7-b0c0-9026e34694d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b2c7247b-6722-41d7-b0c0-9026e34694d5_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_b2c7247b-6722-41d7-b0c0-9026e34694d5" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b2c7247b-6722-41d7-b0c0-9026e34694d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b9994b44-fa3b-4375-9dfc-5a61d9bcb2ea" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_b2c7247b-6722-41d7-b0c0-9026e34694d5" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b9994b44-fa3b-4375-9dfc-5a61d9bcb2ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_5366744f-3a46-4cc7-ab62-cfbf346e7030" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b9994b44-fa3b-4375-9dfc-5a61d9bcb2ea" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_5366744f-3a46-4cc7-ab62-cfbf346e7030" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_ddcccfb5-e521-4a8b-b20b-5d47f0f34216" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b9994b44-fa3b-4375-9dfc-5a61d9bcb2ea" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_ddcccfb5-e521-4a8b-b20b-5d47f0f34216" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_c7dda90d-a76c-45c0-a86d-c4017496d6d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b9994b44-fa3b-4375-9dfc-5a61d9bcb2ea" xlink:to="loc_us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember_c7dda90d-a76c-45c0-a86d-c4017496d6d5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/IncomeTaxes" xlink:type="simple" xlink:href="bkh-20210331.xsd#IncomeTaxes"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/IncomeTaxes" xlink:type="extended" id="i5715c57237394e9ca2eca71be49bd6b8_IncomeTaxes"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/IncomeTaxesWinterStormUriDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#IncomeTaxesWinterStormUriDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/IncomeTaxesWinterStormUriDetails" xlink:type="extended" id="i52f1ebbe7c944272bd2dffe7355c52c1_IncomeTaxesWinterStormUriDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_21f6af13-eb9f-46aa-b88d-d5b758af2fa8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RegulatoryAssets_3d82ad32-65f7-4826-899f-72024521e802" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RegulatoryAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_21f6af13-eb9f-46aa-b88d-d5b758af2fa8" xlink:to="loc_us-gaap_RegulatoryAssets_3d82ad32-65f7-4826-899f-72024521e802" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_09dc92f5-5cc6-4f03-84b9-a7399eacc607" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_21f6af13-eb9f-46aa-b88d-d5b758af2fa8" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_09dc92f5-5cc6-4f03-84b9-a7399eacc607" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_f4e972b7-1275-4e1d-8110-a6a451a3be7b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_21f6af13-eb9f-46aa-b88d-d5b758af2fa8" xlink:to="loc_us-gaap_StatementTable_f4e972b7-1275-4e1d-8110-a6a451a3be7b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_33f77e6b-1bda-4460-8cf6-416eed9cc26b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f4e972b7-1275-4e1d-8110-a6a451a3be7b" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_33f77e6b-1bda-4460-8cf6-416eed9cc26b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_33f77e6b-1bda-4460-8cf6-416eed9cc26b_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_33f77e6b-1bda-4460-8cf6-416eed9cc26b" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_33f77e6b-1bda-4460-8cf6-416eed9cc26b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_2e38ab94-6eb4-4056-add5-02566c27ec2b" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_33f77e6b-1bda-4460-8cf6-416eed9cc26b" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_2e38ab94-6eb4-4056-add5-02566c27ec2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WinterStormUriMember_d6d95ecb-7bab-4f77-b126-5e328e9ec63e" xlink:href="bkh-20210331.xsd#bkh_WinterStormUriMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_2e38ab94-6eb4-4056-add5-02566c27ec2b" xlink:to="loc_bkh_WinterStormUriMember_d6d95ecb-7bab-4f77-b126-5e328e9ec63e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/IncomeTaxesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#IncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/IncomeTaxesDetails" xlink:type="extended" id="ia842eadafd614cabb25384644a3d6dd6_IncomeTaxesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_945fd273-9ab2-459e-bcc4-c6929dceeb80" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_945fd273-9ab2-459e-bcc4-c6929dceeb80" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_f44925c6-cac4-4933-8d29-c7d1112fc0c8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_f44925c6-cac4-4933-8d29-c7d1112fc0c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017AmountTaxBenefitFromBillCredit_59a4026d-fa0c-4d8c-87f9-48d5a81357be" xlink:href="bkh-20210331.xsd#bkh_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017AmountTaxBenefitFromBillCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:to="loc_bkh_EffectiveIncomeTaxRateReconciliationTaxCutsAndJobsActOf2017AmountTaxBenefitFromBillCredit_59a4026d-fa0c-4d8c-87f9-48d5a81357be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_EffectiveIncomeTaxReconciliationTaxBenefitFromAmortizationOfExcessDeferredIncomeTaxes_7f3996a4-a7b7-4cb7-91d2-80b2f4aa59f8" xlink:href="bkh-20210331.xsd#bkh_EffectiveIncomeTaxReconciliationTaxBenefitFromAmortizationOfExcessDeferredIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:to="loc_bkh_EffectiveIncomeTaxReconciliationTaxBenefitFromAmortizationOfExcessDeferredIncomeTaxes_7f3996a4-a7b7-4cb7-91d2-80b2f4aa59f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities_b76936fc-ed23-4ae3-8377-b2bbb3897fd5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:to="loc_us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities_b76936fc-ed23-4ae3-8377-b2bbb3897fd5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c1a74a4b-142f-4b02-8bff-486a86b951d9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5c56974d-f1e6-473d-9c3f-e9752ae8c46c" xlink:to="loc_us-gaap_StatementTable_c1a74a4b-142f-4b02-8bff-486a86b951d9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_f5950cec-1a92-4b0f-a437-6ae71449048d" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c1a74a4b-142f-4b02-8bff-486a86b951d9" xlink:to="loc_dei_LegalEntityAxis_f5950cec-1a92-4b0f-a437-6ae71449048d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_f5950cec-1a92-4b0f-a437-6ae71449048d_default" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_f5950cec-1a92-4b0f-a437-6ae71449048d" xlink:to="loc_dei_EntityDomain_f5950cec-1a92-4b0f-a437-6ae71449048d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_5558e5cd-5d91-4498-bb63-d6125211491d" xlink:href="https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_f5950cec-1a92-4b0f-a437-6ae71449048d" xlink:to="loc_dei_EntityDomain_5558e5cd-5d91-4498-bb63-d6125211491d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ColoradoElectricMember_fcacedd0-0f3b-479e-a82c-a6d0a8389122" xlink:href="bkh-20210331.xsd#bkh_ColoradoElectricMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5558e5cd-5d91-4498-bb63-d6125211491d" xlink:to="loc_bkh_ColoradoElectricMember_fcacedd0-0f3b-479e-a82c-a6d0a8389122" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PublicUtilityAxis_c1c71eb2-ba44-48c2-a4d8-e876025129fd" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PublicUtilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c1a74a4b-142f-4b02-8bff-486a86b951d9" xlink:to="loc_us-gaap_PublicUtilityAxis_c1c71eb2-ba44-48c2-a4d8-e876025129fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilityPlantDomain_c1c71eb2-ba44-48c2-a4d8-e876025129fd_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UtilityPlantDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PublicUtilityAxis_c1c71eb2-ba44-48c2-a4d8-e876025129fd" xlink:to="loc_us-gaap_UtilityPlantDomain_c1c71eb2-ba44-48c2-a4d8-e876025129fd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UtilityPlantDomain_41914132-d2f8-46c2-8c4d-799cf78e21e0" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UtilityPlantDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PublicUtilityAxis_c1c71eb2-ba44-48c2-a4d8-e876025129fd" xlink:to="loc_us-gaap_UtilityPlantDomain_41914132-d2f8-46c2-8c4d-799cf78e21e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_WindAssetsMember_2409f71a-a282-4854-a243-fbb45462af0f" xlink:href="bkh-20210331.xsd#bkh_WindAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UtilityPlantDomain_41914132-d2f8-46c2-8c4d-799cf78e21e0" xlink:to="loc_bkh_WindAssetsMember_2409f71a-a282-4854-a243-fbb45462af0f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/BusinessSegmentInformation" xlink:type="simple" xlink:href="bkh-20210331.xsd#BusinessSegmentInformation"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/BusinessSegmentInformation" xlink:type="extended" id="i7d899754a8ea4bcf86c9a147c3c71303_BusinessSegmentInformation"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/BusinessSegmentInformationTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#BusinessSegmentInformationTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/BusinessSegmentInformationTables" xlink:type="extended" id="i47df7de91625417a86bd4e164626af1d_BusinessSegmentInformationTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/BusinessSegmentInformationSegmentandCorporateAssetsDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#BusinessSegmentInformationSegmentandCorporateAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/BusinessSegmentInformationSegmentandCorporateAssetsDetails" xlink:type="extended" id="i3fc529e81f474e99a31ef4efc7aa3ff2_BusinessSegmentInformationSegmentandCorporateAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_74346122-2027-4865-8906-7568495ad5a5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingAssetReconcilingItemLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_7bf5a68b-7efe-4765-a2de-b6871ae8f254" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_74346122-2027-4865-8906-7568495ad5a5" xlink:to="loc_us-gaap_Assets_7bf5a68b-7efe-4765-a2de-b6871ae8f254" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_bc3979cb-25db-4754-84dc-0d276032f29e" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_74346122-2027-4865-8906-7568495ad5a5" xlink:to="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_bc3979cb-25db-4754-84dc-0d276032f29e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_77f5e8af-39aa-42a6-b74d-772e1d2cb8af" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_bc3979cb-25db-4754-84dc-0d276032f29e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_77f5e8af-39aa-42a6-b74d-772e1d2cb8af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_77f5e8af-39aa-42a6-b74d-772e1d2cb8af_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_77f5e8af-39aa-42a6-b74d-772e1d2cb8af" xlink:to="loc_us-gaap_SegmentDomain_77f5e8af-39aa-42a6-b74d-772e1d2cb8af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_2072f999-9f05-44d9-872d-7ff13102b817" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_77f5e8af-39aa-42a6-b74d-772e1d2cb8af" xlink:to="loc_us-gaap_SegmentDomain_2072f999-9f05-44d9-872d-7ff13102b817" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_7d8cdc29-fb14-4721-bef0-4ac3b99e73e5" xlink:href="bkh-20210331.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2072f999-9f05-44d9-872d-7ff13102b817" xlink:to="loc_bkh_ElectricUtilitiesMember_7d8cdc29-fb14-4721-bef0-4ac3b99e73e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_d621cbd6-72d4-4150-b3f2-efa87ac4b62f" xlink:href="bkh-20210331.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2072f999-9f05-44d9-872d-7ff13102b817" xlink:to="loc_bkh_GasUtilitiesMember_d621cbd6-72d4-4150-b3f2-efa87ac4b62f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_75c69128-2f15-46b4-b672-47558d8a5b3d" xlink:href="bkh-20210331.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2072f999-9f05-44d9-872d-7ff13102b817" xlink:to="loc_bkh_PowerGenerationMember_75c69128-2f15-46b4-b672-47558d8a5b3d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MiningMember_e452a0d5-b263-4399-9c9e-237d4146a103" xlink:href="bkh-20210331.xsd#bkh_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2072f999-9f05-44d9-872d-7ff13102b817" xlink:to="loc_bkh_MiningMember_e452a0d5-b263-4399-9c9e-237d4146a103" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_e9e57fd3-72c3-4a10-b366-31a42806945e" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_bc3979cb-25db-4754-84dc-0d276032f29e" xlink:to="loc_srt_ConsolidationItemsAxis_e9e57fd3-72c3-4a10-b366-31a42806945e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_e9e57fd3-72c3-4a10-b366-31a42806945e_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_e9e57fd3-72c3-4a10-b366-31a42806945e" xlink:to="loc_srt_ConsolidationItemsDomain_e9e57fd3-72c3-4a10-b366-31a42806945e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_42c40d01-e163-4d4e-8ca7-87676338d13a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_e9e57fd3-72c3-4a10-b366-31a42806945e" xlink:to="loc_srt_ConsolidationItemsDomain_42c40d01-e163-4d4e-8ca7-87676338d13a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_ef11e9e3-104d-4446-b1e9-37bddea99032" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_42c40d01-e163-4d4e-8ca7-87676338d13a" xlink:to="loc_us-gaap_CorporateNonSegmentMember_ef11e9e3-104d-4446-b1e9-37bddea99032" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails" xlink:type="extended" id="i1af0044864c94198a60b997686a98854_BusinessSegmentInformationInformationRelatingtoSegmentStatementofIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_a4acb7a6-53d4-4be9-9af1-4167407220eb" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_a4acb7a6-53d4-4be9-9af1-4167407220eb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_612f67ff-cc13-4a8f-a57b-e79a59153702" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_Revenues_612f67ff-cc13-4a8f-a57b-e79a59153702" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_0f2ddbdb-b87e-40fe-80da-a818956109b9" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_OperatingIncomeLoss_0f2ddbdb-b87e-40fe-80da-a818956109b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_0c155035-6e2b-4b30-9655-c12954cb7a94" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_0c155035-6e2b-4b30-9655-c12954cb7a94" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetImpairmentCharges_d4bc32ef-7bdd-4aa3-b001-483200c0e014" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_OtherAssetImpairmentCharges_d4bc32ef-7bdd-4aa3-b001-483200c0e014" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_4d1fc4a5-4e73-4095-872b-f39edf952b04" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_4d1fc4a5-4e73-4095-872b-f39edf952b04" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_a765bd64-e27a-4525-b6ca-50c6367b0bf4" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_a765bd64-e27a-4525-b6ca-50c6367b0bf4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_625e22c0-86c0-4c88-920c-52b10610f6d5" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_ProfitLoss_625e22c0-86c0-4c88-920c-52b10610f6d5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_dbe1f82c-9b54-49c8-b385-73fe1eb9379a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_dbe1f82c-9b54-49c8-b385-73fe1eb9379a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_1f70bc40-10ba-409f-8126-f0a43081f39c" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_NetIncomeLoss_1f70bc40-10ba-409f-8126-f0a43081f39c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5a9371d9-7f23-4044-ac7b-4bd6e5db9e9a" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c5a599a6-62d7-43d4-a5de-075fcac47ed2" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5a9371d9-7f23-4044-ac7b-4bd6e5db9e9a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_02246b36-b427-4fe0-8c23-e3c98e28f642" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5a9371d9-7f23-4044-ac7b-4bd6e5db9e9a" xlink:to="loc_srt_MajorCustomersAxis_02246b36-b427-4fe0-8c23-e3c98e28f642" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_02246b36-b427-4fe0-8c23-e3c98e28f642_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_02246b36-b427-4fe0-8c23-e3c98e28f642" xlink:to="loc_srt_NameOfMajorCustomerDomain_02246b36-b427-4fe0-8c23-e3c98e28f642_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_f5bac377-4b94-4b06-91c1-1ffd12d5aa31" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_02246b36-b427-4fe0-8c23-e3c98e28f642" xlink:to="loc_srt_NameOfMajorCustomerDomain_f5bac377-4b94-4b06-91c1-1ffd12d5aa31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ExternalCustomersMember_7e590ee0-d128-47b9-b908-c9f2e8126669" xlink:href="bkh-20210331.xsd#bkh_ExternalCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f5bac377-4b94-4b06-91c1-1ffd12d5aa31" xlink:to="loc_bkh_ExternalCustomersMember_7e590ee0-d128-47b9-b908-c9f2e8126669" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_IntercompanyCustomersMember_44bc9da1-6e25-458a-9b3d-c91778207035" xlink:href="bkh-20210331.xsd#bkh_IntercompanyCustomersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_f5bac377-4b94-4b06-91c1-1ffd12d5aa31" xlink:to="loc_bkh_IntercompanyCustomersMember_44bc9da1-6e25-458a-9b3d-c91778207035" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_9f35635d-47e9-446d-8bdd-087c1f0cc8ae" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5a9371d9-7f23-4044-ac7b-4bd6e5db9e9a" xlink:to="loc_srt_ProductOrServiceAxis_9f35635d-47e9-446d-8bdd-087c1f0cc8ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_9f35635d-47e9-446d-8bdd-087c1f0cc8ae_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_9f35635d-47e9-446d-8bdd-087c1f0cc8ae" xlink:to="loc_srt_ProductsAndServicesDomain_9f35635d-47e9-446d-8bdd-087c1f0cc8ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_48c5efa1-9993-4534-9bbe-2fe2184fba17" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_9f35635d-47e9-446d-8bdd-087c1f0cc8ae" xlink:to="loc_srt_ProductsAndServicesDomain_48c5efa1-9993-4534-9bbe-2fe2184fba17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_OtherMember_aa185eef-aad1-4a49-8e79-d84e5823c9d7" xlink:href="bkh-20210331.xsd#bkh_OtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_48c5efa1-9993-4534-9bbe-2fe2184fba17" xlink:to="loc_bkh_OtherMember_aa185eef-aad1-4a49-8e79-d84e5823c9d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_168b9dc3-0b8a-4dcc-92c1-60afb14130d8" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5a9371d9-7f23-4044-ac7b-4bd6e5db9e9a" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_168b9dc3-0b8a-4dcc-92c1-60afb14130d8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_168b9dc3-0b8a-4dcc-92c1-60afb14130d8_default" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_168b9dc3-0b8a-4dcc-92c1-60afb14130d8" xlink:to="loc_us-gaap_SegmentDomain_168b9dc3-0b8a-4dcc-92c1-60afb14130d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9cfbe093-dcbe-48af-b9d5-a4c2c9eeff23" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_168b9dc3-0b8a-4dcc-92c1-60afb14130d8" xlink:to="loc_us-gaap_SegmentDomain_9cfbe093-dcbe-48af-b9d5-a4c2c9eeff23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_ElectricUtilitiesMember_8b955873-773a-46bc-95b9-00a931cddc4f" xlink:href="bkh-20210331.xsd#bkh_ElectricUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9cfbe093-dcbe-48af-b9d5-a4c2c9eeff23" xlink:to="loc_bkh_ElectricUtilitiesMember_8b955873-773a-46bc-95b9-00a931cddc4f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_GasUtilitiesMember_4339e814-193f-4422-a751-13673ce815e8" xlink:href="bkh-20210331.xsd#bkh_GasUtilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9cfbe093-dcbe-48af-b9d5-a4c2c9eeff23" xlink:to="loc_bkh_GasUtilitiesMember_4339e814-193f-4422-a751-13673ce815e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_PowerGenerationMember_b4cfc3c0-44f0-4ec0-a414-857665e644d4" xlink:href="bkh-20210331.xsd#bkh_PowerGenerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9cfbe093-dcbe-48af-b9d5-a4c2c9eeff23" xlink:to="loc_bkh_PowerGenerationMember_b4cfc3c0-44f0-4ec0-a414-857665e644d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bkh_MiningMember_8a1dbafe-4949-4dbf-bada-1fe6b4d4f1f8" xlink:href="bkh-20210331.xsd#bkh_MiningMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9cfbe093-dcbe-48af-b9d5-a4c2c9eeff23" xlink:to="loc_bkh_MiningMember_8a1dbafe-4949-4dbf-bada-1fe6b4d4f1f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_0ade8011-7569-49a9-9d24-53d3f690dc6a" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5a9371d9-7f23-4044-ac7b-4bd6e5db9e9a" xlink:to="loc_srt_ConsolidationItemsAxis_0ade8011-7569-49a9-9d24-53d3f690dc6a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_0ade8011-7569-49a9-9d24-53d3f690dc6a_default" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_0ade8011-7569-49a9-9d24-53d3f690dc6a" xlink:to="loc_srt_ConsolidationItemsDomain_0ade8011-7569-49a9-9d24-53d3f690dc6a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_4ee17018-2f7a-4252-9aec-883155c89bea" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_0ade8011-7569-49a9-9d24-53d3f690dc6a" xlink:to="loc_srt_ConsolidationItemsDomain_4ee17018-2f7a-4252-9aec-883155c89bea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_a15fd64d-623d-4560-93ff-5eb42c19b53d" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_4ee17018-2f7a-4252-9aec-883155c89bea" xlink:to="loc_us-gaap_IntersegmentEliminationMember_a15fd64d-623d-4560-93ff-5eb42c19b53d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationEliminationsMember_31caff7a-4d8c-4f3a-a5d7-11e3d8a4ec1f" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ConsolidationEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_4ee17018-2f7a-4252-9aec-883155c89bea" xlink:to="loc_srt_ConsolidationEliminationsMember_31caff7a-4d8c-4f3a-a5d7-11e3d8a4ec1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_adead575-858d-47af-8a3a-e1cb6021a968" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_4ee17018-2f7a-4252-9aec-883155c89bea" xlink:to="loc_us-gaap_CorporateNonSegmentMember_adead575-858d-47af-8a3a-e1cb6021a968" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformation" xlink:type="simple" xlink:href="bkh-20210331.xsd#SelectedBalanceSheetInformation"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformation" xlink:type="extended" id="i19949ff883fc4318a0e730b9052b295c_SelectedBalanceSheetInformation"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationTables" xlink:type="simple" xlink:href="bkh-20210331.xsd#SelectedBalanceSheetInformationTables"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationTables" xlink:type="extended" id="i130dbd95479e4c9b99cf5fe3bb8f5c72_SelectedBalanceSheetInformationTables"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationAccountsReceivableDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#SelectedBalanceSheetInformationAccountsReceivableDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationAccountsReceivableDetails" xlink:type="extended" id="ib19c013698a74bdaaa5bcc1677ce26d6_SelectedBalanceSheetInformationAccountsReceivableDetails"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationChangestoAllowanceforCreditLossesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#SelectedBalanceSheetInformationChangestoAllowanceforCreditLossesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationChangestoAllowanceforCreditLossesDetails" xlink:type="extended" id="i56408939bf774e93a684a84f0d106a67_SelectedBalanceSheetInformationChangestoAllowanceforCreditLossesDetails"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationMaterialsandSuppliesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#SelectedBalanceSheetInformationMaterialsandSuppliesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationMaterialsandSuppliesDetails" xlink:type="extended" id="i169a5b15e41148cc8d9f16e63c44ae65_SelectedBalanceSheetInformationMaterialsandSuppliesDetails"/>
  <link:roleRef roleURI="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationAccruedLiabilitiesDetails" xlink:type="simple" xlink:href="bkh-20210331.xsd#SelectedBalanceSheetInformationAccruedLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.blackhillscorp.com/role/SelectedBalanceSheetInformationAccruedLiabilitiesDetails" xlink:type="extended" id="i10f931d320b94323b06971c48702cd37_SelectedBalanceSheetInformationAccruedLiabilitiesDetails"/>
</link:linkbase>
