-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 IxHp+PtZT7isHaZuoabkQQ==

<SEC-DOCUMENT>0000935836-04-000125.txt : 20040412
<SEC-HEADER>0000935836-04-000125.hdr.sgml : 20040412
<ACCEPTANCE-DATETIME>20040412191630
ACCESSION NUMBER:		0000935836-04-000125
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040407
FILED AS OF DATE:		20040412

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MPOWER HOLDING CORP
		CENTRAL INDEX KEY:			0001117042
		STANDARD INDUSTRIAL CLASSIFICATION:	TELEPHONE COMMUNICATIONS (NO RADIO TELEPHONE) [4813]
		IRS NUMBER:				522232143
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		171 SULLY'S TRAIL
		STREET 2:		STE 202
		CITY:			PITTSFORD
		STATE:			NY
		ZIP:			14534
		BUSINESS PHONE:		7162186550

	MAIL ADDRESS:	
		STREET 1:		171 SULLY'S TRAIL
		STREET 2:		STE 202
		CITY:			PITTSFORD
		STATE:			NY
		ZIP:			14534

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WEST HIGHLAND CAPITAL INC/LHG/WHP/PB/BP
		CENTRAL INDEX KEY:			0000904938
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32941
		FILM NUMBER:		04729426

	BUSINESS ADDRESS:	
		STREET 1:		300 DRAKES LANDING RD SUITE 290
		CITY:			GREENBRAE
		STATE:			CA
		ZIP:			94904
		BUSINESS PHONE:		4154619453

	MAIL ADDRESS:	
		STREET 1:		300 DRAKES LANDING ROAD
		STREET 2:		SUITE 290
		CITY:			GREENBRAE
		STATE:			CA
		ZIP:			94904
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001117042</issuerCik>
        <issuerName>MPOWER HOLDING CORP</issuerName>
        <issuerTradingSymbol>MPOW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000904938</rptOwnerCik>
            <rptOwnerName>WEST HIGHLAND CAPITAL INC/LHG/WHP/PB/BP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>300 DRAKES LANDING ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 290</rptOwnerStreet2>
            <rptOwnerCity>GREENBRAE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94904</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2004-04-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>75000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.3734</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7742104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.3632</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7742104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.34</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7742104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>27069</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7742104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30809</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7742104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting persons consist of (i) Lang H. Gerhard (&quot;Gerhard&quot;), manager of Estero Partners, LLC, sole shareholder of West Highland Capital, Inc., and a general partner of West Highland Partners, L.P.; (ii) West Highland Capital, Inc. (&quot;WHC&quot;), a registered investment adviser and general partner of West Highland Partners, L.P.; (iii) Estero Partners, LLC (&quot;Estero&quot;), a general partner of West Highland Partners, L.P., and (iv) West Highland Partners, L.P. (&quot;WHP&quot;), an investment limited partnership of which Gerhard, WHC and Estero are the general partners. Gerhard, WHC and Estero disclaim membership in a group with any other person within the meaning of Rule 13d-5(b)(i) and Rule 16a-1(a)(1) under the Exchange Act. WHP is filing jointly and disclaims membership in a group with any person within the meaning of Rule 13d-5(b)(i) and Rule 16a-1(a)(1) under the Exchange Act.</footnote>
        <footnote id="F2">Sales on April 7, 8 and 12 were by WHP.</footnote>
        <footnote id="F3">Distributions in kind from WHP to two of its limited partners.</footnote>
        <footnote id="F4">After the transactions reported on this form, each of WHC and Gerhard beneficially owned 8,656,627 shares indirectly, and the number of shares beneficially owned by WHP (directly) and Estero (indirectly) was 7,742,104.</footnote>
        <footnote id="F5">WHP disclaims beneficial ownership of the securities with respect to which its ownership is reported. Each of Gerhard, Estero and WHC disclaims beneficial ownership of the securities he or it beneficially owns, except to the extent, if any, of his or its pecuniary interest therein.</footnote>
        <footnote id="F6">The zeros in the table are placeholders only that are required by the EDGAR software and should be disregarded. There was no price because the shares were distributed in kind.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>West Highland Capital, Inc. By Bonnie George, Chief Operating Officer</signatureName>
        <signatureDate>2004-04-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Lang H. Gerhard By West Highland Capital, Inc., Attorney-in-Fact By Bonnie George, COO</signatureName>
        <signatureDate>2004-04-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Estero Partners, LLC By West Highland Capital, Inc., Attorney-in-Fact By Bonnie George, COO</signatureName>
        <signatureDate>2004-04-12</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>West Highland Partners, L.P. By West Highland Capital, Inc., General Partner By Bonnie George, COO</signatureName>
        <signatureDate>2004-04-12</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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