FORM 4
☐ Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).         	UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
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                      	Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	                      	

1. Name and Address of Reporting Person *

MARSON DEBORAH	2. Issuer Name and Ticker or Trading Symbol

IRON MOUNTAIN INC [ IRM ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable)

_____ Director                    _____ 10% Owner
__X__ Officer (give title below)    _____ Other (specify below)
EVP, General Counsel, Sec.	
(Last)          (First)          (Middle)

C/O IRON MOUNTAIN INCORPORATED, 85 NEW HAMPSHIRE AVENUE, SUITE 150	3. Date of Earliest Transaction (MM/DD/YYYY)

6/15/2023		
(Street)

PORTSMOUTH, NH 03801	4. If Amendment, Date Original Filed (MM/DD/YYYY)

 	6. Individual or Joint/Group Filing (Check Applicable Line)

_X _ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person	
(City)        (State)        (Zip)	Rule 10b5-1(c) Transaction Indication
☒ Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.	

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned	
1.Title of Security
(Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. Code
(Instr. 8)	4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)	5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)	
			Code	V	Amount	(A) or (D)	Price				
Common Stock, par value $.01 per share 	6/15/2023 	 	M(1)	  	2000 	A	$24.80 	64026 	D 	 	
Common Stock, par value $.01 per share 	6/15/2023 	 	S(1)	  	2000 	D	$56.23 	62026 	D 	 	

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)	
1. Title of Derivate Security
(Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. Code
(Instr. 8)	5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)	6. Date Exercisable and Expiration Date	7. Title and Amount of Securities Underlying Derivative Security
(Instr. 3 and 4)	8. Price of Derivative Security
(Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)	
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares					
Employee Stock Option (Right to Buy) 	$24.8 	6/15/2023 	 	M 	  	  	2000  	 (2)	2/13/2024 	Common Stock 	2000.0 	$24.80 	2381 	D 	 	

Explanation of Responses:	
(1) 	This transaction was effected pursuant to a 10b5-1 trading plan which was approved and became effective as of March 15, 2023.	
(2) 	This stock option, representing a right to purchase a total of 4,381 shares, is fully vested.	

Reporting Owners	
Reporting Owner Name / Address	Relationships	
	Director	10% Owner	Officer	Other	
MARSON DEBORAH
C/O IRON MOUNTAIN INCORPORATED
85 NEW HAMPSHIRE AVENUE, SUITE 150
PORTSMOUTH, NH 03801			EVP, General Counsel, Sec.		

Signatures		
/s/ Keely Stewart, under Power of Attorney dated April 17, 2023, from Deborah Marson		6/20/2023	
**Signature of Reporting Person		Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.	
*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).	
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).	
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.	
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.	

POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that I, Deborah Marson, do hereby make, constitute and appoint, Keely Stewart, Assistant Secretary of Iron Mountain Incorporated and Luke Cummiskey, Manager, Senior Corporate Counsel, acting singly, to be my lawful attorney-in-fact for me and to do any and all acts which I could do in connection with any filings required by Section 16 of the Securities Exchange Act of 1934, including, without limitation, the preparation, signing and filing of Forms 3, 4 and 5 ("Section 16 Filings").

Among the powers granted to my attorney-in-fact are:

To prepare, sign and file with the Securities and Exchange Commission and the New York Stock Exchange the Section 16 Filings, in my name or stead, and any and all such further documents as he/she may deem necessary or advisable in order to carry out the required Section 16 Filings and the powers granted to him/her by these presents.

This Power of Attorney shall remain in effect until revoked by the undersigned in writing.

IN WITNESS WHEREOF, I have hereunto set my hand and seal this 17 day of April, 2023.

__/s/ Deborah Marson______
Name:  Deborah Marson