SecProbe.io

Mailstop 3233

July 14, 2017

Via E -Mail
Stuart B. Brown
Executive Vice President and Chief Financial Officer
Iron Mountain Incorporated
One Federal Street
Boston, MA  02110

Re: Iron Mountain Incorporated
 Form 10 -K for the fiscal year ended December 31, 2016
Filed February 23, 2017
File No. 1-13045

Dear Mr. Brown:

We have limited our review  of your filing  to the financial statements and related
disclosures and have the following comments.  In some of our comments, we may ask you to
provide us with information so we may better understand your disclosure.

Please respond to these comments within ten business days by providing the requested
informa tion or advise us as soon as possible when you will respond.  If you do not believe our
comments apply to your facts and circumstances, please tell us why in your response.

After reviewing your response to these comments, we may have additional comments .

Form 10 -K for fiscal year ended December 31, 2016

Item 2. Properties, page 26
1. As a lessor of storage facilities to customers, please tell us what consideration you gave
to including a lease expiration table for the facilities related to your storage rental
business, including (i) the number of tenants whose leases will expire by year, (ii) the
total area in square feet covered by such leases, (iii) the annual rent represented by such
leases and (iv) the percentage of gross annual rent rep resented by such leases.

Stuart B. Brown
Iron Mountain Incorporated
July 14, 2017
Page 2

 Item 7. Management’s Discussion and Analysis of Financial Condition and Results of
Operations

Impairment of Tangible and Intangible Assets, page 42
2. You indicate that for reporting units representing approximately 16% of your total
goodwill balance as of December 31, 2016, the estimated fair value as of October 1, 2016
closely approximates carrying value.  In future periodic filings for each reporting unit
with an estimated fair value that is not significantly in excess its carrying value, please
consider expanding your disclosure to provide a  description of the key assumptions used
in valuing the reporting units and a description of potential events or changes in
circumstances that could reasonably be expected to have a negative impact on the
estimated fair value of the reporting unit.  Refer to Section V. in SEC Interpretive
Release 33 -8350.
Financial Instruments and  Debt, page 65
3. We note your fixed charge coverage ratio of 2.4x as of December 31, 2016 and 2015 as
disclosed on page 68 and 116.  Please tell us how this differs from the Ratio of Earnings
to Fixed Charges, calculated as 1.4x in Exhibit 12.

Item 15. Exhi bits and Financial Statements

Schedule III – Schedule of Real Estate and Accumulated Depreciation, page 159
4. Please reconcile for us the gross carrying amount of real estate and accumulated
depreciation to amounts provided elsewhere in your annual report.  Additionally in future
periodic filings, disclose in a note to the gross amount column your aggregate cost for
Federal income tax purposes  in accordance with Rule 12 -28 of Regulation S -X.

We remind you that the company and its management are responsible for the a ccuracy
and adequacy of their disclosures, notwithstanding any review, comments, action or absence of
action by the staff.

You may contact Mark Rakip, Staff Accountant at 202.551.3573 or me at 202.551.3429
if you have questions regarding comments on the  financial statements and related matters

Sincerely,

 /s/ Kristi Marrone

Kristi Marrone
Staff Accountant
Office of Real Estate and
Commodities