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

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-11-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000100885</issuerCik>
        <issuerName>UNION PACIFIC CORP</issuerName>
        <issuerTradingSymbol>UNP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001241205</rptOwnerCik>
            <rptOwnerName>DONOHUE THOMAS J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1615 H STREET NW</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20062-2000</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</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2003-11-19</value>
                <footnoteId id="F2"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1345</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1345</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5086</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>

    </derivativeTable>

    <footnotes>
        <footnote id="F1">Distribution ratio for Phantom Stock Units is 1:1.        </footnote>
        <footnote id="F2">Phantom Stock Units awarded upon the completion of five years of service on the Board of Directors, calculated as of November 19, 2003.</footnote>
        <footnote id="F3">Phantom Stock Units are payable in cash only commencing at retirement.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Carl W. von Bernuth, Attorney-in-Fact  For: Thomas Donohue</signatureName>
        <signatureDate>2003-11-20</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2003-11-19
0
0000100885
UNION PACIFIC CORP
UNP
0001241205
DONOHUE THOMAS J
1615 H STREET NW
WASHINGTON
DC
20062-2000
1
0
0
0
Phantom Stock
0
2003-11-19
4
A
0
1345
0
A
Common Stock
1345
5086
D
Distribution ratio for Phantom Stock Units is 1:1.
Phantom Stock Units awarded upon the completion of five years of service on the Board of Directors, calculated as of November 19, 2003.
Phantom Stock Units are payable in cash only commencing at retirement.
By: Carl W. von Bernuth, Attorney-in-Fact  For: Thomas Donohue
2003-11-20