<SUBMISSION>
<ACCESSION-NUMBER>0001252748-03-000001
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030707
<FILING-DATE>20030709
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>MARLOW JOHN K
<CIK>0001252748
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-23976
<FILM-NUMBER>03780689
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>112 W KING STREET
<CITY>STRASBURG
<STATE>VA
<ZIP>22657
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>FIRST NATIONAL CORP /VA/
<CIK>0000719402
<ASSIGNED-SIC>6022
<IRS-NUMBER>541231965
<STATE-OF-INCORPORATION>VA
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>100 WEST KING STREET
<CITY>STRASBURG
<STATE>VA
<ZIP>22657
<PHONE>7034659121
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>100 WEST KING STREET
<CITY>STRASBURG
<STATE>VA
<ZIP>22657
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-07-07</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000719402</issuerCik>
        <issuerName>FIRST NATIONAL CORP /VA/</issuerName>
        <issuerTradingSymbol>FXNC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001252748</rptOwnerCik>
            <rptOwnerName>MARLOW JOHN K</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-07-07</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>800</value>
            </transactionShares>
            <transactionValue>
                <value>27.4</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>1100</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>Marlow Investments LLC</value>
            </natureOfOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-07-07</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>200</value>
            </transactionShares>
            <transactionValue>
                <value>27</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>1300</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>I</value>
            </directOrIndirectOwnership>
            <natureOfOwnership>
                <value>Marlow Investments LLC</value>
                <footnoteId id="F1"/>
            </natureOfOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <footnotes>
        <footnote id="F1">Mr. Marlow also beneficially owns 900 shares in direct ownership form.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Nancy T. Fitchett, by power of atty.     Director</signatureName>
        <signatureDate>2003-07-09</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
