<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-10-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000352955</issuerCik>
        <issuerName>CKX LANDS, INC.</issuerName>
        <issuerTradingSymbol>CKX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001375131</rptOwnerCik>
            <rptOwnerName>Ottley Properties, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>337 METAIRIE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 202</rptOwnerStreet2>
            <rptOwnerCity>METAIRIE</rptOwnerCity>
            <rptOwnerState>LA</rptOwnerState>
            <rptOwnerZipCode>70005</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001375144</rptOwnerCik>
            <rptOwnerName>WHITE MICHAEL B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>337 METAIRIE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 202</rptOwnerStreet2>
            <rptOwnerCity>METAIRIE</rptOwnerCity>
            <rptOwnerState>LA</rptOwnerState>
            <rptOwnerZipCode>70005</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-10-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>252</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.7204</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>358850</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares are held directly by Ottley Properties, LLC.  Michael B. White, as sole manager of Ottley Properties, LLC, may be deemed to have an indirect interest in the shares, but disclaims such interest except of his pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>\s\ Michael B. White as sole manager of Ottley Properties, LLC</signatureName>
        <signatureDate>2016-10-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>\s\ Michael B. White</signatureName>
        <signatureDate>2016-10-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
