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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-10-02</periodOfReport>

    <issuer>
        <issuerCik>0001428205</issuerCik>
        <issuerName>Armour Residential REIT, Inc.</issuerName>
        <issuerTradingSymbol>ARR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001469064</rptOwnerCik>
            <rptOwnerName>ULM SCOTT</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3001 OCEAN DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 201</rptOwnerStreet2>
            <rptOwnerCity>VERO BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>32963</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <officerTitle>Co-CEO and CIO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-10-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>19724</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>179172</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">See Remarks</footnote>
    </footnotes>

    <remarks>On October 2, 2013, the reporting person elected to redeem 2,551 shares out of 4,875 shares of vested phantom stock previously granted under ARMOUR Residential REIT, Inc.'s Amended and Restated 2009 Stock Incentive Plan (the &quot;Incentive Plan&quot;) into 2,551 shares of ARMOUR common stock. The reporting person also elected to redeem the remaining 2,324 shares of vested phantom stock, but immediately forfeited those shares to pay income taxes on the vesting grant. The 4,875 shares are part of, and relate to, phantom stock vesting over a 5-year period, which was reported on Form 4s filed by the reporting person on April 4, 2011 and April 3, 2012. In addition, on October 2, 2013, the reporting person elected to redeem 6,725 shares out of 13,450 shares of vested phantom stock into 6,725 shares of ARMOUR common stock. The reporting person also elected to redeem the remaining 6,725 shares of vested phantom stock, but immediately forfeited those shares to pay income taxes on the vesting grant. The 13,450 shares are part of, and relate to, phantom stock vesting over a 5-year period, which was reported on a Form 4 filed by the reporting person on April 11, 2012. On October 2, 2013, the reporting person also elected to redeem 10,448 shares out of 26,504 shares of vested phantom stock into 10,448 shares of ARMOUR common stock. The person also elected to redeem the remaining 16,056 shares of vested phantom stock, but immediately forfeited those shares to pay income taxes on the vesting grant. The 26,504 shares are part of, and relate to, phantom stock vesting over a 5-year period, which was reported on a Form 4 filed by the reporting person on March 21, 2013.</remarks>

    <ownerSignature>
        <signatureName>/s/ Scott J. Ulm</signatureName>
        <signatureDate>2013-10-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
