-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 Pnunr6+Pff6KAg7uay5vieJ5GuiBvvbYGcjLHxUUibP8fIQzSmzJc79QnkF1BN0V
 /0Js+xU59UBLHQhXrPdNmg==

<SEC-DOCUMENT>0001130464-05-000445.txt : 20051202
<SEC-HEADER>0001130464-05-000445.hdr.sgml : 20051202
<ACCEPTANCE-DATETIME>20051202191407
ACCESSION NUMBER:		0001130464-05-000445
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051130
FILED AS OF DATE:		20051202
DATE AS OF CHANGE:		20051202

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BLACK HILLS CORP /SD/
		CENTRAL INDEX KEY:			0001130464
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		IRS NUMBER:				460458824
		STATE OF INCORPORATION:			SD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		625 9TH STREET
		STREET 2:		PO BOX 1400
		CITY:			RAPID CITY
		STATE:			SD
		ZIP:			57709
		BUSINESS PHONE:		6057212343

	MAIL ADDRESS:	
		STREET 1:		625 9TH STREET
		STREET 2:		PO BOX 1400
		CITY:			RAPID
		STATE:			SD
		ZIP:			57709

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BLACK HILLS HOLDING CORP
		DATE OF NAME CHANGE:	20001222

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KORPAN RICHARD
		CENTRAL INDEX KEY:			0001022294

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31303
		FILM NUMBER:		051242372

	BUSINESS ADDRESS:	
		STREET 1:		ONE PROGRESS PLZ
		STREET 2:		SUITE 2600
		CITY:			ST PETERBURG
		STATE:			FL
		ZIP:			33701
		BUSINESS PHONE:		8138246531

	MAIL ADDRESS:	
		STREET 1:		ONE PROGRESS PLZ
		STREET 2:		SUITE 2600
		CITY:			ST PETERSBURG
		STATE:			FL
		ZIP:			33701
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-11-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001130464</issuerCik>
        <issuerName>BLACK HILLS CORP /SD/</issuerName>
        <issuerTradingSymbol>bkh</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001022294</rptOwnerCik>
            <rptOwnerName>KORPAN RICHARD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 1400</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>RAPID CITY</rptOwnerCity>
            <rptOwnerState>SD</rptOwnerState>
            <rptOwnerZipCode>57701-1400</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-11-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>191.519</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.55</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1387.083</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-12-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11.922</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>37.2308</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1399.005</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">1 for 1 Conversion Ratio</footnote>
        <footnote id="F2">Derivative security is exercisable upon retirement under terms of the agreement.</footnote>
        <footnote id="F3">Derivative Security expires upon retirement under terms of the agreement.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Roxann R. Basham, by power of attorney for Richard Korpan</signatureName>
        <signatureDate>2005-12-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
