<SEC-DOCUMENT>0001020569-23-000100.txt : 20230414
<SEC-HEADER>0001020569-23-000100.hdr.sgml : 20230414
<ACCEPTANCE-DATETIME>20230414163812
ACCESSION NUMBER:		0001020569-23-000100
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230412
FILED AS OF DATE:		20230414
DATE AS OF CHANGE:		20230414

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Simons Doyle
		CENTRAL INDEX KEY:			0001185922

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13045
		FILM NUMBER:		23821698

	MAIL ADDRESS:	
		STREET 1:		220 OCCIDENTAL AVENUE SOUTH
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98104

	FORMER NAME:	
		FORMER CONFORMED NAME:	SIMONS DOYLE R
		DATE OF NAME CHANGE:	20020904

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IRON MOUNTAIN INC
		CENTRAL INDEX KEY:			0001020569
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				232588479
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		85 NEW HAMPSHIRE AVENUE, SUITE 150
		STREET 2:		PEASE INTERNATIONAL TRADEPORT
		CITY:			PORTSMOUTH
		STATE:			NH
		ZIP:			03801
		BUSINESS PHONE:		617-535-4781

	MAIL ADDRESS:	
		STREET 1:		ONE FEDERAL STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	IRON MOUNTAIN INC/PA
		DATE OF NAME CHANGE:	20000201

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PIERCE LEAHY CORP
		DATE OF NAME CHANGE:	19960807
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_168150468017437.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0407</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-04-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001020569</issuerCik>
        <issuerName>IRON MOUNTAIN INC</issuerName>
        <issuerTradingSymbol>IRM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001185922</rptOwnerCik>
            <rptOwnerName>Simons Doyle</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O IRON MOUNTAIN INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>85 NEW HAMPSHIRE AVENUE, SUITE 150</rptOwnerStreet2>
            <rptOwnerCity>PORTSMOUTH</rptOwnerCity>
            <rptOwnerState>NH</rptOwnerState>
            <rptOwnerZipCode>03801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2023-04-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>599.256</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>54.23</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>599.256</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30010.167</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the &quot;Phantom Shares&quot;) will become payable in shares of Iron Mountain Incorporated common stock (&quot;Common Stock&quot;) following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of Common Stock.</footnote>
        <footnote id="F2">These shares give effect to the Reporting Person's quarterly cash compensation for services on the Iron Mountain Incorporated board of directors as if reinvested in Phantom Shares.</footnote>
        <footnote id="F3">The price reported in Column 8 is a weighted average price. These shares of Iron Mountain Incorporated Common Stock were sold in multiple transactions at prices ranging from $54.199 to $54.259, inclusive. The Reporting Person undertakes to provide Iron Mountain Incorporated (the &quot;Company&quot;), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares of Common Stock sold at each separate price within the ranges set forth in this footnote (3).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Elizabeth Tammaro, under Power of Attorney dated January 2, 2020 from Doyle R. Simons</signatureName>
        <signatureDate>2023-04-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
