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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-01-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000726958</issuerCik>
        <issuerName>CASEYS GENERAL STORES INC</issuerName>
        <issuerTradingSymbol>CASY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001901354</rptOwnerCik>
            <rptOwnerName>Lindsey Katrina S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE SE CONVENIENCE BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ANKENY</rptOwnerCity>
            <rptOwnerState>IA</rptOwnerState>
            <rptOwnerZipCode>50021</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Legal Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-01-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>716</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2913</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-01-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>283</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>397.93</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2630</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>149</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Voting and tender rights under 401k plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
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            <transactionDate>
                <value>2025-01-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>716</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>716</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
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            <exerciseDate>
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            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>102</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>102</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F6"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>286</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>286</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
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            <exerciseDate>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>631</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>631</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
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            <exerciseDate>
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            <expirationDate>
                <footnoteId id="F8"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>735</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>735</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Closing price of Casey's General Stores, Inc. Common Stock on January 3, 2025.</footnote>
        <footnote id="F2">Allocated to 401k plan account as of April 30, 2024. Does not include any shares allocated by the plan trustee after that date.</footnote>
        <footnote id="F3">Each restricted stock unit represents the right to receive, following vesting, one share of Common Stock.</footnote>
        <footnote id="F4">Pursuant to 2018 Stock Incentive Plan and in accordance with the terms and conditions of a &quot;make-whole award&quot; of January 3, 2022, granted in conjunction with commencement of employment as Casey's Chief Legal Officer. The remainder of this award vested on January 3, 2025.</footnote>
        <footnote id="F5">Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest on March 2, 2025.</footnote>
        <footnote id="F6">Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest  June 15, 2025. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2025, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.</footnote>
        <footnote id="F7">Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest in equal installments  on June 15, 2025 and June 15, 2026. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2026, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.</footnote>
        <footnote id="F8">Pursuant to the terms and conditions of the 2018 Stock Incentive Plan,  this award will vest in equal installments on June 15, 2025, June 15, 2026, and June 15, 2027.  Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2027,  but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Scott Faber, under Power of Attorney dated December 17, 2021</signatureName>
        <signatureDate>2025-01-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2025-01-03
0
0000726958
CASEYS GENERAL STORES INC
CASY
0001901354
Lindsey Katrina S
ONE SE CONVENIENCE BLVD.
ANKENY
IA
50021
0
1
0
0
Chief Legal Officer
0
Common Stock
2025-01-03
4
M
0
716
0
A
2913
D
Common Stock
2025-01-03
4
F
0
283
397.93
D
2630
D
Common Stock
149
I
Voting and tender rights under 401k plan
Restricted stock units
2025-01-03
4
M
0
716
0
D
Common Stock
716
0
D
Restricted stock units
Common Stock
102
102
D
Restricted stock units
Common Stock
286
286
D
Restricted stock units
Common Stock
631
631
D
Restricted stock units
Common Stock
735
735
D
Closing price of Casey's General Stores, Inc. Common Stock on January 3, 2025.
Allocated to 401k plan account as of April 30, 2024. Does not include any shares allocated by the plan trustee after that date.
Each restricted stock unit represents the right to receive, following vesting, one share of Common Stock.
Pursuant to 2018 Stock Incentive Plan and in accordance with the terms and conditions of a "make-whole award" of January 3, 2022, granted in conjunction with commencement of employment as Casey's Chief Legal Officer. The remainder of this award vested on January 3, 2025.
Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest on March 2, 2025.
Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest  June 15, 2025. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2025, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.
Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest in equal installments  on June 15, 2025 and June 15, 2026. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2026, but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.
Pursuant to the terms and conditions of the 2018 Stock Incentive Plan,  this award will vest in equal installments on June 15, 2025, June 15, 2026, and June 15, 2027.  Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2027,  but which are subject to the satisfaction of certain performance criteria other than solely the price of Casey's Common Stock; the final amount of shares earned, if any, will be reported upon vest and satisfaction of those performance measures.
Scott Faber, under Power of Attorney dated December 17, 2021
2025-01-07