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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-06-04</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000106926</issuerCik>
        <issuerName>WHITNEY HOLDING CORP</issuerName>
        <issuerTradingSymbol>WTNY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001453842</rptOwnerCik>
            <rptOwnerName>Cowell Elizabeth L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>228 ST. CHARLES AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW ORLEANS</rptOwnerCity>
            <rptOwnerState>LA</rptOwnerState>
            <rptOwnerZipCode>70130</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock no par value</value>
            </securityTitle>
            <transactionDate>
                <value>2011-06-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-06-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>7500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Comm stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-06-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Comm stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Disposed of pursuant to merger agreement between the Company and Hancock Holding Company (&quot;Hancock&quot;).  For each share of Company common stock, the reporting person received .418 of a share of Hancock common stock having a market value of $32.04 per share on the effective date of the merger.</footnote>
        <footnote id="F2">The restricted stock units vest (become non-forfeitable) on the third anniversary of the grant date or earlier upon a change in control of the Company.  Vested restricted stock units convert to shares of common stock  on a 1-for-1 basis on the later of (i) within 30 days following the vesting date or (ii) the earliest permissible date such units may convert to shares of common stock as a result of the Company's receipt of financial assistance under the Department of the Treasury's Troubled Asset Relief Program.</footnote>
        <footnote id="F3">The restricted stock units were assumed by Hancock in the Merger. Each restricted stock unit was converted into the right to receive .418 of a share of Hancock common stock, payable within 60 days following the merger.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Patricia K. Loupe, Sr. Assistant Corporate Secretary for Whitney Holding Corporation and attorney-in-fact</signatureName>
        <signatureDate>2011-06-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0303
4
2011-06-04
1
0000106926
WHITNEY HOLDING CORP
WTNY
0001453842
Cowell Elizabeth L
228 ST. CHARLES AVENUE
NEW ORLEANS
LA
70130
0
1
0
0
Executive Vice President
Common stock no par value
2011-06-04
4
D
0
2500
D
0
D
Restricted stock units
2011-06-04
4
D
0
7500
D
Comm stock
7500
0
D
Restricted stock units
2011-06-04
4
D
0
8000
D
Comm stock
8000
0
D
Disposed of pursuant to merger agreement between the Company and Hancock Holding Company ("Hancock").  For each share of Company common stock, the reporting person received .418 of a share of Hancock common stock having a market value of $32.04 per share on the effective date of the merger.
The restricted stock units vest (become non-forfeitable) on the third anniversary of the grant date or earlier upon a change in control of the Company.  Vested restricted stock units convert to shares of common stock  on a 1-for-1 basis on the later of (i) within 30 days following the vesting date or (ii) the earliest permissible date such units may convert to shares of common stock as a result of the Company's receipt of financial assistance under the Department of the Treasury's Troubled Asset Relief Program.
The restricted stock units were assumed by Hancock in the Merger. Each restricted stock unit was converted into the right to receive .418 of a share of Hancock common stock, payable within 60 days following the merger.
Patricia K. Loupe, Sr. Assistant Corporate Secretary for Whitney Holding Corporation and attorney-in-fact
2011-06-07