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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
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 HjrV3MRS/tAPualk4IdIcw==

<SEC-DOCUMENT>0001179110-07-005263.txt : 20070302
<SEC-HEADER>0001179110-07-005263.hdr.sgml : 20070302
<ACCEPTANCE-DATETIME>20070302173431
ACCESSION NUMBER:		0001179110-07-005263
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070228
FILED AS OF DATE:		20070302
DATE AS OF CHANGE:		20070302

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			US LEC CORP
		CENTRAL INDEX KEY:			0001054290
		STANDARD INDUSTRIAL CLASSIFICATION:	TELEPHONE COMMUNICATIONS (NO RADIO TELEPHONE) [4813]
		IRS NUMBER:				562065535
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6801 MORRISON BOULEVARD
		STREET 2:		MORROCROFT III
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211
		BUSINESS PHONE:		704-319-1000

	MAIL ADDRESS:	
		STREET 1:		6801 MORRISON BOULEVARD
		STREET 2:		MORROCROFT III
		CITY:			CHARLOTTE
		STATE:			NC
		ZIP:			28211

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LEE THOMAS H EQUITY FUND IV LP
		CENTRAL INDEX KEY:			0001053032
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24061
		FILM NUMBER:		07668983

	BUSINESS ADDRESS:	
		STREET 1:		C/O THOMAS H. LEE PARTNERS, L.P.
		STREET 2:		100 FEDERAL STREET, 35TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
		BUSINESS PHONE:		6172271050

	MAIL ADDRESS:	
		STREET 1:		C/O THOMAS H. LEE PARTNERS, L.P.
		STREET 2:		100 FEDERAL STREET, 35TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-02-28</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001054290</issuerCik>
        <issuerName>US LEC CORP</issuerName>
        <issuerTradingSymbol>CLEC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001053032</rptOwnerCik>
            <rptOwnerName>LEE THOMAS H EQUITY FUND IV LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THOMAS H. LEE PARTNERS, L.P.</rptOwnerStreet1>
            <rptOwnerStreet2>100 FEDERAL STREET, 35TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Series A Convertible Preferred Stock</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>28.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-02-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>125843</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1000</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4493936</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The holder of shares of Series A Convertible Preferred Stock (the &quot;Preferred Stock&quot;) has the right, at his option, to convert each such share into a number of shares of Class A Common Stock (the &quot;Common Stock&quot;) determined by dividing $1,000.00 by the conversion price in effect at the time of conversion ($28.002 as of February 28, 2007).</footnote>
        <footnote id="F2">The Reporting Person held 83,533 shares of Preferred Stock as of April 11, 2000 and has subsequently received 42,310 shares in stock dividends which are exempt under Rule 16(b)-3, resulting in total holdings as of February 28, 2007 of 125,843 shares of Preferred Stock, which were repurchased by the Issuer on February 28, 2007.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Anthony J. DiNovi</signatureName>
        <signatureDate>2007-03-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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