<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-02-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000736772</issuerCik>
        <issuerName>CNB FINANCIAL CORP/PA</issuerName>
        <issuerTradingSymbol>CCNE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001694708</rptOwnerCik>
            <rptOwnerName>Shilling Steven R Shaffner</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>31 S 2ND ST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CLEARFIELD</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>16830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP/Chief Wealth Mngt Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-02-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1099</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.35</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8718</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-02-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>371</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.35</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8347</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Depositary Shares</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>400</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2997.083</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 401K Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These securities were issued to the reporting person pursuant to the CNB Financial Corporation 2019 Stock Incentive Plan, which provided for the conversion of performance units into a number of shares of common stock based on the Issuer's performance over a three year designated performance period.</footnote>
        <footnote id="F2">Reflects shares of common stock surrendered to the Issuer to satisfy tax withholding obligations in connection with the Performance Award.</footnote>
        <footnote id="F3">Each Depositary Share represents a 1/40th interest in a share of the Issuer's 7.125% Series A Fixed-Rate Non-Cumulative Perpetual Preferred Stock, no par value per share.  Depositary Shares were purchased in an underwritten public offering.</footnote>
        <footnote id="F4">Each Depositary Share represents a 1/40th interest in a share of the Issuer's 7.125% Series A Fixed-Rate Non-Cumulative Perpetual Preferred Stock, no par value per share. Depositary Shares were purchased in an underwritten public offering.</footnote>
        <footnote id="F5">The amount of securities beneficially owned have been adjusted to reflect the latest plan statement.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jessica A. Zupich, Attorney-in-Fact</signatureName>
        <signatureDate>2024-02-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2024-02-26
0
0000736772
CNB FINANCIAL CORP/PA
CCNE
0001694708
Shilling Steven R Shaffner
31 S 2ND ST
CLEARFIELD
PA
16830
0
1
0
0
EVP/Chief Wealth Mngt Officer
0
Common Stock
2024-02-26
5
A
0
E
1099
21.35
A
8718
D
Common Stock
2024-02-26
5
F
0
E
371
21.35
D
8347
D
Depositary Shares
400
D
Common Stock
2997.083
I
By 401K Plan
These securities were issued to the reporting person pursuant to the CNB Financial Corporation 2019 Stock Incentive Plan, which provided for the conversion of performance units into a number of shares of common stock based on the Issuer's performance over a three year designated performance period.
Reflects shares of common stock surrendered to the Issuer to satisfy tax withholding obligations in connection with the Performance Award.
Each Depositary Share represents a 1/40th interest in a share of the Issuer's 7.125% Series A Fixed-Rate Non-Cumulative Perpetual Preferred Stock, no par value per share.  Depositary Shares were purchased in an underwritten public offering.
Each Depositary Share represents a 1/40th interest in a share of the Issuer's 7.125% Series A Fixed-Rate Non-Cumulative Perpetual Preferred Stock, no par value per share. Depositary Shares were purchased in an underwritten public offering.
The amount of securities beneficially owned have been adjusted to reflect the latest plan statement.
/s/ Jessica A. Zupich, Attorney-in-Fact
2024-02-26