<SEC-DOCUMENT>0000034782-18-000026.txt : 20180215
<SEC-HEADER>0000034782-18-000026.hdr.sgml : 20180215
<ACCEPTANCE-DATETIME>20180215164023
ACCESSION NUMBER:		0000034782-18-000026
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180214
FILED AS OF DATE:		20180215
DATE AS OF CHANGE:		20180215

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Buhr Jeffrey L
		CENTRAL INDEX KEY:			0001599829

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-06233
		FILM NUMBER:		18618258

	MAIL ADDRESS:	
		STREET 1:		PO BOX 1602
		CITY:			SOUTH BEND
		STATE:			IN
		ZIP:			46634

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			1ST SOURCE CORP
		CENTRAL INDEX KEY:			0000034782
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				351068133
		STATE OF INCORPORATION:			IN
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		100 NORTH MICHIGAN STREET
		CITY:			SOUTH BEND
		STATE:			IN
		ZIP:			46601
		BUSINESS PHONE:		5742352702

	MAIL ADDRESS:	
		STREET 1:		P O BOX 1602
		STREET 2:		P O BOX 1602
		CITY:			SOUTH BEND
		STATE:			IN
		ZIP:			46634

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FBT BANCORP INC
		DATE OF NAME CHANGE:	19820818
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_151873080742737.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-02-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000034782</issuerCik>
        <issuerName>1ST SOURCE CORP</issuerName>
        <issuerTradingSymbol>SRCE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001599829</rptOwnerCik>
            <rptOwnerName>Buhr Jeffrey L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 1602</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SOUTH BEND</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46634</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-02-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1739</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>52911</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4336</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 401(k)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">EIP awards for 2017.</footnote>
        <footnote id="F2">Between January 1, 2017 and December 31, 2017, Mr. Buhr acquired 215 shares of 1st Source Corporation common stock under the 401(k) plan. The information in this report is based on a plan statement dated December 31, 2017.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John B. Griffith, Attorney-in-Fact</signatureName>
        <signatureDate>2018-02-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
