Schedule III Real Estate and Accumulated Depreciation

12 Months Ended

Dec. 31, 2012

Schedule III Real Estate and Accumulated Depreciation

Schedule III Real Estate and Accumulated Depreciation

Schedule III
Real Estate and Accumulated Depreciation

December 31, 2012

								Costs Capitalized				Gross Amount Carried at
				Initial Cost				Subsequent to Acquisition				December 31, 2012								Year
						Building and				Building and				Building and				Accumulated Depreciation		Acquired
Property Name	Location	Encumbrances		Land		Improvements		Land		Improvements		Land		Improvements		Total		at December 31, 2012		or Leased
	(In thousands)
SV1	San Jose, CA	$	59,750	$	6,863	$	91,719	$	—	$	15,023	$	6,863	$	106,742	$	113,605	$	7,342	2010
SV2	Milpitas, CA	—		5,086		5,046		—		17,502		5,086		22,548		27,634		8,073		2006
SV3	Santa Clara, CA	—		3,972		3,482		—		41,731		3,972		45,213		49,185		11,246		2007
SV4	Santa Clara, CA	—		4,442		3,716		—		79,920		4,442		83,636		88,078		3,136		2007
Santa Clara Campus	Santa Clara, CA	—		11,486		9,240		1,131		4,088		12,617		13,328		25,945		2,115		2007
BO1	Somerville, MA	—		6,100		26,748		—		43,652		6,100		70,400		76,500		18,682		2007
NY1	New York, NY	—		—		—		—		31,292		—		31,292		31,292		9,199		2007
VA1	Reston, VA	—		12,100		32,939		—		74,783		12,100		107,722		119,822		17,901		2007
DC1	Washington, DC	—		—		4,797		—		1,996		—		6,793		6,793		1,197		2010
CH1	Chicago, IL	—		5,493		49,522		—		25,921		5,493		75,443		80,936		6,008		2010
LA1	Los Angeles, CA	—		—		41,099		—		10,735		—		51,834		51,834		8,505		2010
LA2	Los Angeles, CA	—		28,467		94,114		—		21,155		28,467		115,269		143,736		10,102		2010
MI1	Miami, FL	—		728		9,325		—		432		728		9,757		10,485		964		2010
DE1	Denver, CO	—		—		37				232		—		269		269		18		2012
DE2	Denver, CO	—		—		4				5		—		9		9		2		2012
	Total	$	59,750	$	84,737	$	371,788	$	1,131	$	368,467	$	85,868	$	740,255	$	826,123	$	104,490

The aggregate cost of the total properties for federal income tax purposes was approximately $812.2 million (unaudited) at December 31, 2012.

See accompanying report of independent registered public accounting firm.

 Schedule III

 Real Estate and Accumulated Depreciation

 December 31, 2012

The following table reconciles the historical cost and accumulated depreciation of the CoreSite Realty Corporation properties for the years ended December 31, 2012, 2011 and 2010:

	2012		2011		2010
			(In thousands)
Property
Balance, beginning of period	$	738,596	$	622,622	$	234,262
Additions - property acquisitions	—		—		332,128
Additions - improvements	87,527		115,974		56,232
Balance, end of period	$	826,123	$	738,596	$	622,622
Accumulated Depreciation
Balance, beginning of period	$	64,428	$	32,943	$	16,207
Additions - depreciation, net of disposals	40,062		31,485		16,736
Balance, end of period	$	104,490	$	64,428	$	32,943

See accompanying report of independent registered public accounting firm.