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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-12-13</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001791716</rptOwnerCik>
            <rptOwnerName>Brennan Thomas P JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE SE CONVENIENCE BOULEVARD</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 Merch. Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-12-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1430</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>276.11</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7375</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-12-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>220</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7155</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>231</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Voting and tender rights under 401k plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>397</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>397</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>900</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>900</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Restricted stock units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1233</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1233</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Allocated to Mr. Brennan's 401k plan account as of April 30, 2023. Does not include any shares allocated by the plan trustee after that date.</footnote>
        <footnote id="F2">Each restricted stock unit represents the right to receive, following vesting, one share of Common Stock.</footnote>
        <footnote id="F3">Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest on June 15, 2024. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2024, 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="F4">Pursuant to terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest in equal installments on June 15, 2024 and 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="F5">Pursuant to terms and conditions of 2018 Stock Incentive Plan. This award will vest in equal installments on June 15, 2024, 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>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Scott Faber, under Power of Attorney dated October 17, 2019</signatureName>
        <signatureDate>2023-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2023-12-13
0
0000726958
CASEYS GENERAL STORES INC
CASY
0001791716
Brennan Thomas P JR
ONE SE CONVENIENCE BOULEVARD
ANKENY
IA
50021
0
1
0
0
Chief Merch. Officer
0
Common Stock
2023-12-13
4
S
0
1430
276.11
D
7375
D
Common Stock
2023-12-13
4
G
0
220
0
D
7155
D
Common Stock
231
I
Voting and tender rights under 401k plan
Restricted stock units
Common Stock
397
397
D
Restricted stock units
Common Stock
900
900
D
Restricted stock units
Common Stock
1233
1233
D
Allocated to Mr. Brennan's 401k plan account as of April 30, 2023. 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 terms and conditions of 2018 Stock Incentive Plan. The remainder of this award will vest on June 15, 2024. Not included in the reported award amount is a target amount of performance-based restricted stock units that will vest on June 15, 2024, 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, 2024 and 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. This award will vest in equal installments on June 15, 2024, 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.
Scott Faber, under Power of Attorney dated October 17, 2019
2023-12-13