-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 RBwivtck96pI9qd8Zh+bCQbiKpjI5XWkVnOPmM66HadyXI0jMZYsQJVsNpCOJ709
 KXQfil06jDSIEdm0FFF02g==

<SEC-DOCUMENT>0001209191-07-015765.txt : 20070305
<SEC-HEADER>0001209191-07-015765.hdr.sgml : 20070305
<ACCEPTANCE-DATETIME>20070305212145
ACCESSION NUMBER:		0001209191-07-015765
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070301
FILED AS OF DATE:		20070305
DATE AS OF CHANGE:		20070305

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Columbia Equity Trust, Inc.
		CENTRAL INDEX KEY:			0001316710
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				201978579
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1750 H STREET, N.W.
		STREET 2:		SUITE 500
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006
		BUSINESS PHONE:		(202) 303-3060

	MAIL ADDRESS:	
		STREET 1:		1750 H STREET, N.W.
		STREET 2:		SUITE 500
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Owen Rebecca L
		CENTRAL INDEX KEY:			0001331684

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32536
		FILM NUMBER:		07673191

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		202-303-3060

	MAIL ADDRESS:	
		STREET 1:		1750 H STREET, SUITE 500
		STREET 2:		COLUMBIA EQUITY TRUST, INC.
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-03-01</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001316710</issuerCik>
        <issuerName>Columbia Equity Trust, Inc.</issuerName>
        <issuerTradingSymbol>COE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001331684</rptOwnerCik>
            <rptOwnerName>Owen Rebecca L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1750 H STREET, N.W.</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 500</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>LTIP Units</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-03-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.50</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2006-07-05</value>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Units</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">LTIP Units are convertible into Units of Limited Partnership interest of Columbia Equity, LP (&quot;Units&quot;) on a one-for-one basis.  These Expire upon dissolution or expiration of the term of Columbia Equity, LP, whichever occurs first.</footnote>
        <footnote id="F2">Disposed of for $19.50 in cash pursuant to a merger agreement.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John A. Schissel
Attorney-in-Fact</signatureName>
        <signatureDate>2007-03-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
