<SEC-DOCUMENT>0001140361-16-086739.txt : 20161115
<SEC-HEADER>0001140361-16-086739.hdr.sgml : 20161115
<ACCEPTANCE-DATETIME>20161115135109
ACCESSION NUMBER:		0001140361-16-086739
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20161114
FILED AS OF DATE:		20161115
DATE AS OF CHANGE:		20161115

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNITED SECURITY BANCSHARES
		CENTRAL INDEX KEY:			0001137547
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		IRS NUMBER:				912112732
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1525 E SHAW AVENUE
		CITY:			FRESO
		STATE:			CA
		ZIP:			93710

	MAIL ADDRESS:	
		STREET 1:		1525 E SHAW AVENUE
		CITY:			FRESNO
		STATE:			CA
		ZIP:			93710

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ELLITHORPE G THOMPSON
		CENTRAL INDEX KEY:			0001145948

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-32897
		FILM NUMBER:		161999027

	MAIL ADDRESS:	
		STREET 1:		1525 E SHAW AVE
		CITY:			FRESNO
		STATE:			CA
		ZIP:			93710
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-11-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001137547</issuerCik>
        <issuerName>UNITED SECURITY BANCSHARES</issuerName>
        <issuerTradingSymbol>UBFO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001145948</rptOwnerCik>
            <rptOwnerName>ELLITHORPE G THOMPSON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2126 INYO STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FRESNO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>93721</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>UBFO COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2016-11-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3035</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.2219</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>137644</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents indirect ownership of 82,285 shares of common stock held in reporting person's SD IRA and direct ownership of 55,359 shares of common stock held by reporting person as trustee of a trust.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/S/ TOM  ELLITHORPE</signatureName>
        <signatureDate>2016-11-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
