-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 MexZ68vpOe8bPor9SF/0C5C/uxFk4KL4zeO2Qsyr8l7ctSCg618FrpgfagE23luG
 CHinvdBNMXn47QQ4OaGrdA==

<SEC-DOCUMENT>0001056916-06-000001.txt : 20060112
<SEC-HEADER>0001056916-06-000001.hdr.sgml : 20060112
<ACCEPTANCE-DATETIME>20060112161252
ACCESSION NUMBER:		0001056916-06-000001
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051231
FILED AS OF DATE:		20060112
DATE AS OF CHANGE:		20060112

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			POTLATCH CORP
		CENTRAL INDEX KEY:			0000079716
		STANDARD INDUSTRIAL CLASSIFICATION:	PAPER MILLS [2621]
		IRS NUMBER:				820156045
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		601 W RIVERSIDE AVE
		STREET 2:		STE 1100
		CITY:			SPOKANE
		STATE:			WA
		ZIP:			99201
		BUSINESS PHONE:		5098351500

	MAIL ADDRESS:	
		STREET 1:		601 W RIVERSIDE AVE SUITE 1100
		CITY:			SPOKANE
		STATE:			WA
		ZIP:			99201

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	POTLATCH FORESTS INC
		DATE OF NAME CHANGE:	19730827

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WEYERHAEUSER WILLIAM T
		CENTRAL INDEX KEY:			0001056916

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05313
		FILM NUMBER:		06527302

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 1278
		CITY:			TACOMA
		STATE:			WA
		ZIP:			98401
		BUSINESS PHONE:		2532728336

	MAIL ADDRESS:	
		STREET 1:		PO BOX 1278
		CITY:			TACOMA
		STATE:			WA
		ZIP:			98401
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2005-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000079716</issuerCik>
        <issuerName>POTLATCH CORP</issuerName>
        <issuerTradingSymbol>PCH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001056916</rptOwnerCik>
            <rptOwnerName>WEYERHAEUSER WILLIAM T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 1278</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>TACOMA</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98401</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1050</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>49500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Beneficiary &amp; Trustee of WBW Trust #1</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>21030</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>I disclaim beneficial ownership of these shs held by a trust for my mother of which I am a trustee</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2700</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>I disclaim beneficial ownership of these shares owned directly by my wife</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionCoding>
                <transactionFormType></transactionFormType>
            </transactionCoding>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>29775</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>I disclaim beneficial ownership of these shs held in a trust for my sister of which I am a trustee</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2005-09-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>53.48</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>I disclaim beneficial ownership of these shares owned directly by my son</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares owned by adult child of reporting person who is no longer a resident of reporting person's household.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>William T. Weyerhaeuser</signatureName>
        <signatureDate>2006-01-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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