<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="..\4_X02.xsl"?><ownershipDocument>    <schemaVersion>X0202</schemaVersion>    <documentType>4</documentType>    <periodOfReport>2004-05-27</periodOfReport>    <issuer>        <issuerCik>0001169029</issuerCik>        <issuerName>BLACKROCK MARYLAND MUNICIPAL BOND TRUST</issuerName>        <issuerTradingSymbol>BZM</issuerTradingSymbol>    </issuer>    <reportingOwner>        <reportingOwnerId>            <rptOwnerCik>0001215052</rptOwnerCik>            <rptOwnerName>BLACKROCK FUNDING INC</rptOwnerName>        </reportingOwnerId>        <reportingOwnerAddress>            <rptOwnerStreet1>C/O BLACKROCK FINANCIAL MANAGEMENT, INC</rptOwnerStreet1>            <rptOwnerStreet2>40 EAST 52ND STREET</rptOwnerStreet2>            <rptOwnerCity>NEW YORK</rptOwnerCity>            <rptOwnerState>NY</rptOwnerState>            <rptOwnerZipCode>10022</rptOwnerZipCode>            <rptOwnerStateDescription></rptOwnerStateDescription>        </reportingOwnerAddress>        <reportingOwnerRelationship>            <isDirector>0</isDirector>            <isOfficer>0</isOfficer>            <isTenPercentOwner>0</isTenPercentOwner>            <isOther>1</isOther>            <otherText>Affiliate of the Adviser</otherText>        </reportingOwnerRelationship>    </reportingOwner>    <nonDerivativeTable>        <nonDerivativeTransaction>            <securityTitle>                <value>Shares of Common Stock (par value $0.001 per share)</value>            </securityTitle>            <transactionDate>                <value>2004-05-27</value>            </transactionDate>            <transactionCoding>                <transactionFormType>4</transactionFormType>                <transactionCode>S</transactionCode>                <equitySwapInvolved>0</equitySwapInvolved>            </transactionCoding>            <transactionAmounts>                <transactionShares>                    <value>7679</value>                </transactionShares>                <transactionPricePerShare>                    <value>13.82</value>                </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>    <footnotes></footnotes>    <remarks></remarks>    <ownerSignature>        <signatureName>Salvatore Rappa</signatureName>        <signatureDate>2004-06-01</signatureDate>    </ownerSignature></ownershipDocument>
