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	File No. 017637-1043

VIA EDGAR CORRESPONDENCE

Duc Dang
Attorney—Advisor
Division of Corporation Finance
Securities and Exchange Commission
100 F Street, N.E.
Washington, D.C. 20549

Re: CoreSite Realty Corporation
Amendment No. 5 to Registration Statement on Form S-11
Filed September 13, 2010
SEC File No. 333-166810

Dear Mr. Dang:

     Pursuant to our telephonic conversation on September 22, 2010, with respect to the above-referenced Amendment No. 5 to the Registration Statement on Form S-11 (as it may be amended or supplemented, “Amendment No. 5”), we are hereby confirming our agreement to your requests on behalf of CoreSite Realty Corporation (the “Company”).

     As discussed during our telephonic conversation on September 22, 2010, in connection with the Company’s filing of its final prospects pursuant to Rule 424(b), the Company will:

• identify the initial lenders under its new revolving credit facility; and

• affirmatively state that, commencing with its short taxable year ending December 31, 2010, the Company has been organized in conformity with the requirements for qualification and taxation as a REIT under the Code and that its proposed method of operation will enable it to continue to meet the requirements for qualification and taxation as a REIT under the Code.

     Thank you in advance for your cooperation in connection with this matter.

Very truly yours,
 

/s/ Patrick H. Shannon  

Patrick H. Shannon 

of LATHAM & WATKINS LLP 

cc: Yolanda Crittendon, Securities and Exchange Commission
Cicely LaMothe, Securities and Exchange Commission
Stacie Gorman, Securities and Exchange Commission
Thomas M. Ray, CoreSite Realty Corporation
Edward J. Schneidman, Esq., Mayer Brown LLP
John P. Berkery, Esq., Mayer Brown LLP
Jeffrey J. Knight, KPMG LLP
Raymond Y. Lin, Esq., Latham & Watkins LLP
Brandon J. Bortner, Esq., Latham & Watkins LLP