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

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
    <periodOfReport>2004-01-05</periodOfReport>
    <notSubjectToSection16>1</notSubjectToSection16>
    <issuer>
        <issuerCik>0000831959</issuerCik>
        <issuerName>UNITED NATIONAL BANCORP</issuerName>
        <issuerTradingSymbol>UNBJ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000922708</rptOwnerCik>
            <rptOwnerName>RUS ARLYN D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>913 SUNSET RIDGE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BRIDGEWATER</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08807</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
        <isDirector>1</isDirector>
        <isOfficer>0</isOfficer>
        <isTenPercentOwner>0</isTenPercentOwner>
        <isOther>0</isOther>
    </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
    <derivativeTransaction>
        <securityTitle>
            <value>Non-Qualified Stock Option</value>
        </securityTitle>
        <conversionOrExercisePrice>
            <value>22.05</value>
        </conversionOrExercisePrice>
        <transactionDate>
            <value>2004-01-01</value>
        </transactionDate>
        <deemedExecutionDate>
            <value>2004-01-01</value>
        </deemedExecutionDate>
    <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>J</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
        <footnoteId id="F1"/>
    </transactionCoding>
        <transactionAmounts>
            <transactionShares>
                <value>2000</value>
            </transactionShares>
            <transactionPricePerShare>
                <value>35.83</value>
            </transactionPricePerShare>
            <transactionAcquiredDisposedCode>
                <value>D</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <exerciseDate>
            <value>2004-01-01</value>
        </exerciseDate>
        <expirationDate>
            <value>2004-01-01</value>
        </expirationDate>
        <underlyingSecurity>
            <underlyingSecurityTitle>
                <value>Common Stock</value>
            </underlyingSecurityTitle>
            <underlyingSecurityShares>
                <value>2000</value>
            </underlyingSecurityShares>
        </underlyingSecurity>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>0</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </derivativeTransaction>

    </derivativeTable>
    <footnotes>
        <footnote id="F1">As a result of the completion of the acquisition of United National Bancorp by The PNC Financial Services Group, Inc. on 1/1/04, all stock option vesting accelerated and options were paid in cash.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Arlyn D. Rus</signatureName>
        <signatureDate>2004-01-05</signatureDate>
    </ownerSignature>

</ownershipDocument>

