<SEC-DOCUMENT>0000949157-21-000111.txt : 20210702
<SEC-HEADER>0000949157-21-000111.hdr.sgml : 20210702
<ACCEPTANCE-DATETIME>20210702163430
ACCESSION NUMBER:		0000949157-21-000111
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20210701
FILED AS OF DATE:		20210702
DATE AS OF CHANGE:		20210702

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Gary Jesse E
		CENTRAL INDEX KEY:			0001568817

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34474
		FILM NUMBER:		211070704

	MAIL ADDRESS:	
		STREET 1:		2511 GARDEN ROAD
		STREET 2:		BUILDING A, SUITE 200
		CITY:			MONTEREY
		STATE:			CA
		ZIP:			93940

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CENTURY ALUMINUM CO
		CENTRAL INDEX KEY:			0000949157
		STANDARD INDUSTRIAL CLASSIFICATION:	PRIMARY PRODUCTION OF ALUMINUM [3334]
		IRS NUMBER:				133070826
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1 SOUTH WACKER DRIVE
		STREET 2:		SUITE 1000
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3126963101

	MAIL ADDRESS:	
		STREET 1:		1 SOUTH WACKER DRIVE
		STREET 2:		SUITE 1000
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_162525805573751.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-07-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000949157</issuerCik>
        <issuerName>CENTURY ALUMINUM CO</issuerName>
        <issuerTradingSymbol>CENX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001568817</rptOwnerCik>
            <rptOwnerName>Gary Jesse E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CENTURY ALUMINUM COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>ONE SOUTH WACKER DRIVE, SUITE 1000</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President &amp; CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-07-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>171276</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>332732</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>64400</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents awards granted to the Reporting Person consisting of (i) 13,740 time vesting share units under the Issuer's 2021-2023 Long-Term Incentive Plan under Rule 16b-3(d), all of which will vest in the ordinary course on the last day of the Plan Period, December 31, 2023 and (ii) 157,536 time vesting share units, 78,768 of which vest in the ordinary course on July 1, 2022, 47,261 of which vest in the ordinary course on July 1, 2023 and 31,507 of which vest in the ordinary course on July 1, 2024.</footnote>
        <footnote id="F2">Includes unvested time vesting share units granted to the Reporting Person (i) pursuant to Issuer's 2019-2021, 2020-2022 and 2021-2023 Long-Term Incentive Plans under Rule 16b-3(d) and (ii) 157,536 time vesting share units, 78,768 of which vest in the ordinary course on July 1, 2022, 47,261 of which vest in the ordinary course on July 1, 2023 and 31,507 of which vest in the ordinary course on July 1, 2024.</footnote>
        <footnote id="F3">Represents shares transferred by the Reporting Person to a self-settled, revocable trust for estate planning purposes. The Reporting Person serves as the trustee of the trust.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John DeZee, Attorney-in-Fact for Jesse E. Gary</signatureName>
        <signatureDate>2021-07-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>poa-section16forms345fordz.htm
<DESCRIPTION>POWER OF ATTORNEY (GARY) - SECTION 16 FILINGS
<TEXT>
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<pre>

POWER OF ATTORNEY

        KNOW ALL BY THESE PRESENTS, that the undersigned hereby constitutes and appoints John DeZee, signing singly, the undersigned's true and lawful attorney-in-fact to:

(1)    execute for and on behalf of the undersigned, in the undersigned's capacity as an officer and/or director of Century Aluminum Company (the "Company") Forms 3, 4 and 5 (and any amendments thereto) in accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the rules thereunder;

(2)    do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete and execute any such Form 3, 4 or 5, complete and execute any amendments thereto, and timely file such form with the U.S. Securities and Exchange Commission (the "SEC"), including without limitation the filing of a Form ID or any other documents necessary or appropriate to enable the undersigned to file the Forms 3, 4 and 5 electronically with the SEC; and

(3)    take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in such attorney-in-fact's discretion.

    The undersigned hereby grants to such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted.  The undersigned acknowledges that the foregoing attorney-in-fact, in serving in such capacity at the request of the undersigned, are not assuming, nor is the Company assuming, any of the undersigned's responsibilities to comply with the Exchange Act.

       This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to execute such filings in accordance with the Exchange Act and the rules thereunder, unless earlier revoked by the undersigned in a signed writing delivered to the foregoing attorney-in-fact.

    IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 1st day of July, 2021.


/s/ Jesse E. Gary
Signature

Jesse Gary
Print Name




2



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