UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the
Securities Exchange Act of 1934 (Amendment No. )

☑ Filed by the Registrant ☐ Filed by a party other than the Registrant

CHECK THE APPROPRIATE BOX:
☐	Preliminary Proxy Statement
☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
☐	Definitive Proxy Statement
☑	Definitive Additional Materials
☐	Soliciting Material under §240.14a-12

Iron Mountain Inc.

(Name of Registrant as Specified In Its Charter)
(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

PAYMENT OF FILING FEE (CHECK ALL BOXES THAT APPLY):
☑	No fee required
☐	Fee paid previously with preliminary materials
☐	Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

IRON MOUNTAIN INCORPORATED INVESTOR RELATIONS ONE FEDERAL STREET BOSTON, MA 02110	Your Vote Counts! IRON MOUNTAIN INCORPORATED 2022 Annual Meeting Vote by May 9, 2022 11:59 PM ET
D76983-P66263

You invested in IRON MOUNTAIN INCORPORATED and it’s time to vote!
You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on May 10, 2022.

Get informed before you vote
View the Notice and Proxy Statement and Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 26, 2022. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy.

	For complete information and to vote, visit www.ProxyVote.com
	Control #

Smartphone users Point your camera here and vote without entering a control number		Vote Virtually at the Meeting* May 10, 2022 9:00 AM EDT
	Virtually at: www.virtualshareholdermeeting.com/IRM2022

*Please check the meeting materials for any special requirements for meeting attendance.

Vote at www.ProxyVote.com

THIS IS NOT A VOTABLE BALLOT

This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters.

Voting Items		Board Recommends
1.	For the election of eleven (11) directors to the Iron Mountain Incorporated Board of Directors for a one-year term or until their successors are elected and qualified.
	Nominees:
1a.	Jennifer Allerton		For
1b.	Pamela M. Arway		For
1c.	Clarke H. Bailey		For
1d.	Kent P. Dauten		For
1e.	Monte Ford		For
1f.	Robin L. Matlock		For
1g.	William L. Meaney		For
1h.	Wendy J. Murdock		For
1i.	Walter C. Rakowich		For
1j.	Doyle R. Simons		For
1k.	Alfred J. Verrecchia		For
2.	The approval of a non-binding, advisory resolution approving the compensation of our named executive officers as described in the Iron Mountain Incorporated Proxy Statement.		For
3.	The ratification of the selection by the Audit Committee of Deloitte & Touche LLP as Iron Mountain Incorporated’s independent registered public accounting firm for the year ending December 31, 2022.		For
NOTE: In their discretion, the proxies are authorized to vote upon such other business as may properly come before the Annual Meeting of Stockholders or any postponement or adjournment thereof.

Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Sign up for E-delivery”.

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