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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-11-30</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000020212</issuerCik>
        <issuerName>CHURCHILL DOWNS Inc</issuerName>
        <issuerTradingSymbol>CHDN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001117661</rptOwnerCik>
            <rptOwnerName>Duchossois Group, Inc.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>444 WEST LAKE, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001667474</rptOwnerCik>
            <rptOwnerName>CDI Holdings LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>444 W. LAKE, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000923231</rptOwnerCik>
            <rptOwnerName>DUCHOSSOIS RICHARD L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>444 W. LAKE, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001078976</rptOwnerCik>
            <rptOwnerName>DUCHOSSOIS CRAIG J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>444 W. LAKE, SUITE 2000</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2017-06-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1000000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>158.78</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1000000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By CDI Holdings LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <transactionDate>
                <value>2016-11-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>137141</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>148.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spring Creek Investors II, LLC</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F5"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3373</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By The Chamberlin Group, Inc.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F6"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>165947</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By RLD Revocable Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F6"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4548</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Richard L. Duchossois</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F7"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17646</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By CJD Revocable Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This form is a joint filing by The Duchossois Group, Inc. (&quot;TDG&quot;), CDI Holdings LLC (&quot;Holdings&quot;), Richard L. Duchossois and Craig J. Duchossois. TDG is the sole member and manager of Holdings. Richard L. Duchossois and Craig J. Duchossois, by virtue of their relationship with TDG, may be deemed to beneficially own the shares of common stock of Churchill Downs Incorporated (the &quot;Issuer&quot;) that are owned by Holdings and which TDG may be deemed to beneficially own. Richard L. Duchossois and Craig J. Duchossois disclaim beneficial ownership with respect to the shares of common stock of the Issuer owned by Holdings, except with respect to each individual's pecuniary interest in such shares attributable to him by virtue of his respective equity interest in TDG.</footnote>
        <footnote id="F2">These are the same shares reflected in the Form 4 filings of Richard L. Duchossois and Craig J. Duchossois that are being filed simultaneous herewith.</footnote>
        <footnote id="F3">Richard L. Duchossois and Craig J. Duchossois, by virtue of their relationship with Spring Creek Investors II LLC, may be deemed to benefically own the shares of common stock of the Issuer that are owned by Spring Creek Investors II LLC. Richard L. Duchossois and Craig J. Duchossois disclaim beneficial ownership with respect to the shares of common stock of the Issuer owned by Spring Creek Investors II LLC, except with respect to each individual's pecuniary interest in such shares.</footnote>
        <footnote id="F4">These are the same shares reflected in the Form 4 filings of Richard L. Duchossois and Craig J. Duchossois that were filed on 12/2/2016.</footnote>
        <footnote id="F5">Richard L. Duchossois and Craig J. Duchossois, by virtue of their relationship with The Chamberlain Group, Inc. and TDG, may be deemed to beneficially own the shares of common stock of the Issuer that are owned by The Chamberlain Group, Inc. and which TDG may be deemed to beneficially own. Richard L. Duchossois and Craig J. Duchossois disclaim beneficial ownership with respect to the shares of common stock of the Issuer owned by The Chamberlain Group, Inc., except with respect to each individual's pecuniary interest in such shares attributable to him by virtue of his respective equity interest in TDG.</footnote>
        <footnote id="F6">Reflects shares of common stock of the Issuer beneficially owned by Richard L. Duchossois and not by TDG, Holdings or Craig J. Duchossois.</footnote>
        <footnote id="F7">Reflects shares of common stock of the Issuer beneficially owned by Craig J. Duchossois and not by TDG, Holdings or Richard L. Duchossois.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Eric A. Reeves, attorney-in-fact for Richard L. Duchossois</signatureName>
        <signatureDate>2017-06-13</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Eric A. Reeves, attorney-in-fact for Craig J. Duchossois</signatureName>
        <signatureDate>2017-06-13</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Eric A. Reeves, Vice President and General Counsel of The Duchossois Group, Inc.</signatureName>
        <signatureDate>2017-06-13</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Eric A. Reeves, Vice President and General Counsel of CDI Holdings LLC</signatureName>
        <signatureDate>2017-06-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
