Annual report pursuant to Section 13 and 15(d)

Schedule III - Real Estate and Accumulated Depreciation

v3.22.0.1
Schedule III - Real Estate and Accumulated Depreciation
 12 Months Ended
Dec. 31, 2021
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]  
Schedule III-Real Estate and Accumulated Depreciation
Initial Cost Gross Amounts Carried
At Close of Period
Property (Type) (1) Location Encumbrances (2) Land Building
and Land Improvements		 Costs Capitalized Subsequent to Acquisition Land Building
and Land Improvements		 Total
(3)		 Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5)
100 Light Street (O) Baltimore, MD $ —  $ 26,715  $ 58,002  $ 36,662  $ 26,715  $ 94,664  $ 121,379  $ (25,616) 1973/2011 8/7/2015
100 Secured Gateway (O) Huntsville, AL —  —  71,089  —  —  71,089  71,089  (2,340) 2020 3/23/2010
1000 Redstone Gateway (O) Huntsville, AL 9,281  —  20,533  76  —  20,609  20,609  (4,525) 2013 3/23/2010
1100 Redstone Gateway (O) Huntsville, AL 9,913  —  19,593  88  —  19,681  19,681  (3,912) 2014 3/23/2010
114 National Business Parkway (O) Annapolis Junction, MD —  364  3,109  404  364  3,513  3,877  (1,679) 2002 6/30/2000
1200 Redstone Gateway (O) Huntsville, AL 11,441  —  22,389  141  —  22,530  22,530  (4,509) 2013 3/23/2010
1201 M Street SE (O) Washington, DC —  —  49,775  10,290  —  60,065  60,065  (21,051) 2001 9/28/2010
1201 Winterson Road (O) Linthicum, MD —  2,130  17,009  901  2,130  17,910  20,040  (5,952) 1985/2017 4/30/1998
1220 12th Street SE (O) Washington, DC —  —  42,464  9,749  —  52,213  52,213  (19,797) 2003 9/28/2010
1243 Winterson Road (L) Linthicum, MD —  630  —  —  630  —  630  —  (6) 12/19/2001
131 National Business Parkway (O) Annapolis Junction, MD —  1,906  7,623  5,893  1,906  13,516  15,422  (7,872) 1990 9/28/1998
132 National Business Parkway (O) Annapolis Junction, MD —  2,917  12,259  4,876  2,917  17,135  20,052  (11,075) 2000 5/28/1999
133 National Business Parkway (O) Annapolis Junction, MD —  2,517  10,068  6,731  2,517  16,799  19,316  (10,935) 1997 9/28/1998
134 National Business Parkway (O) Annapolis Junction, MD —  3,684  7,517  5,726  3,684  13,243  16,927  (8,014) 1999 11/13/1998
1340 Ashton Road (O) Hanover, MD —  905  3,620  2,540  905  6,160  7,065  (3,423) 1989 4/28/1999
13450 Sunrise Valley Drive (O) Herndon, VA —  1,386  5,576  4,952  1,386  10,528  11,914  (6,583) 1998 7/25/2003
13454 Sunrise Valley Drive (O) Herndon, VA —  2,847  11,986  9,240  2,847  21,226  24,073  (12,918) 1998 7/25/2003
135 National Business Parkway (O) Annapolis Junction, MD —  2,484  9,750  7,003  2,484  16,753  19,237  (10,779) 1998 12/30/1998
1362 Mellon Road (O) Hanover, MD —  950  3,864  1,632  950  5,496  6,446  (1,193) 2006 2/10/2006
13857 McLearen Road (O) Herndon, VA —  3,507  30,177  4,915  3,507  35,092  38,599  (13,842) 2007 7/11/2012
140 National Business Parkway (O) Annapolis Junction, MD —  3,407  24,167  1,784  3,407  25,951  29,358  (11,646) 2003 12/31/2003
141 National Business Parkway (O) Annapolis Junction, MD —  2,398  9,538  4,832  2,398  14,370  16,768  (9,758) 1990 9/28/1998
14280 Park Meadow Drive (O) Chantilly, VA —  3,731  15,953  5,500  3,731  21,453  25,184  (10,469) 1999 9/29/2004
1460 Dorsey Road (L) Hanover, MD —  1,577  115  —  1,577  115  1,692  —  (6) 2/28/2006
14840 Conference Center Drive (O) Chantilly, VA —  1,572  8,175  5,730  1,572  13,905  15,477  (7,895) 2000 7/25/2003
14850 Conference Center Drive (O) Chantilly, VA —  1,615  8,358  5,345  1,615  13,703  15,318  (7,455) 2000 7/25/2003
14900 Conference Center Drive (O) Chantilly, VA —  3,436  14,402  9,282  3,436  23,684  27,120  (14,024) 1999 7/25/2003
1501 South Clinton Street (O) Baltimore, MD —  27,964  51,990  23,731  27,964  75,721  103,685  (31,475) 2006 10/27/2009
15049 Conference Center Drive (O) Chantilly, VA —  4,415  20,365  17,846  4,415  38,211  42,626  (20,360) 1997 8/14/2002
15059 Conference Center Drive (O) Chantilly, VA —  5,753  13,615  4,543  5,753  18,158  23,911  (10,774) 2000 8/14/2002
1550 West Nursery Road (O) Linthicum, MD —  14,071  16,930  —  14,071  16,930  31,001  (6,678) 2009 10/28/2009
1560 West Nursery Road (O) Linthicum, MD —  1,441  113  —  1,441  113  1,554  (22) 2014 10/28/2009
1610 West Nursery Road (O) Linthicum, MD —  259  246  —  259  246  505  (29) 2016 4/30/1998
1616 West Nursery Road (O) Linthicum, MD —  393  3,323  75  393  3,398  3,791  (358) 2017 4/30/1998
1622 West Nursery Road (O) Linthicum, MD —  393  2,542  —  393  2,542  2,935  (308) 2016 4/30/1998
16442 Commerce Drive (O) Dahlgren, VA —  613  2,582  1,135  613  3,717  4,330  (1,988) 2002 12/21/2004
16480 Commerce Drive (O) Dahlgren, VA —  1,856  7,425  2,619  1,856  10,044  11,900  (4,754) 2000 12/28/2004
Initial Cost Gross Amounts Carried
At Close of Period
Property (Type) (1) Location Encumbrances (2) Land Building
and Land Improvements		 Costs Capitalized Subsequent to Acquisition Land Building
and Land Improvements		 Total
(3)		 Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5)
16501 Commerce Drive (O) Dahlgren, VA —  522  2,090  1,040  522  3,130  3,652  (1,544) 2002 12/21/2004
16539 Commerce Drive (O) Dahlgren, VA —  688  2,860  2,326  688  5,186  5,874  (3,058) 1990 12/21/2004
16541 Commerce Drive (O) Dahlgren, VA —  773  3,094  2,596  773  5,690  6,463  (2,989) 1996 12/21/2004
16543 Commerce Drive (O) Dahlgren, VA —  436  1,742  838  436  2,580  3,016  (1,348) 2002 12/21/2004
1751 Pinnacle Drive (O) McLean, VA —  10,486  42,339  33,825  10,486  76,164  86,650  (42,720) 1989/1995 9/23/2004
1753 Pinnacle Drive (O) McLean, VA —  8,275  34,353  24,092  8,275  58,445  66,720  (28,325) 1976/2004 9/23/2004
206 Research Boulevard (O) Aberdeen, MD —  —  —  —  —  —  —  —  2012 9/14/2007
209 Research Boulevard (O) Aberdeen, MD —  134  1,711  543  134  2,254  2,388  (687) 2010 9/14/2007
210 Research Boulevard (O) Aberdeen, MD —  113  1,402  426  113  1,828  1,941  (543) 2010 9/14/2007
2100 L Street (O) Washington, DC —  57,385  94,152  —  57,385  94,152  151,537  (1,987) 2020 8/11/2015
2100 Rideout Road (O) Huntsville, AL —  —  7,336  2,995  —  10,331  10,331  (2,274) 2016 3/23/2010
22289 Exploration Drive (O) Lexington Park, MD —  1,422  5,719  2,129  1,422  7,848  9,270  (4,369) 2000 3/24/2004
22299 Exploration Drive (O) Lexington Park, MD —  1,362  5,791  3,049  1,362  8,840  10,202  (5,297) 1998 3/24/2004
22300 Exploration Drive (O) Lexington Park, MD —  1,094  5,038  2,770  1,094  7,808  8,902  (4,134) 1997 11/9/2004
22309 Exploration Drive (O) Lexington Park, MD —  2,243  10,419  8,114  2,243  18,533  20,776  (8,947) 1984/1997 3/24/2004
23535 Cottonwood Parkway (O) California, MD —  692  3,051  648  692  3,699  4,391  (2,193) 1984 3/24/2004
250 W Pratt St (O) Baltimore, MD —  8,057  34,588  18,482  8,057  53,070  61,127  (18,418) 1985 3/19/2015
2600 Park Tower Drive (O) Vienna, VA —  20,284  34,443  4,621  20,284  39,064  59,348  (8,392) 1999 4/15/2015
2691 Technology Drive (O) Annapolis Junction, MD —  2,098  17,334  5,565  2,098  22,899  24,997  (12,224) 2005 5/26/2000
2701 Technology Drive (O) Annapolis Junction, MD —  1,737  15,266  7,033  1,737  22,299  24,036  (13,380) 2001 5/26/2000
2711 Technology Drive (O) Annapolis Junction, MD —  2,251  21,611  4,335  2,251  25,946  28,197  (14,988) 2002 11/13/2000
2720 Technology Drive (O) Annapolis Junction, MD —  3,863  29,272  2,897  3,863  32,169  36,032  (14,204) 2004 1/31/2002
2721 Technology Drive (O) Annapolis Junction, MD —  4,611  14,597  3,783  4,611  18,380  22,991  (10,792) 2000 10/21/1999
2730 Hercules Road (O) Annapolis Junction, MD —  8,737  31,612  8,998  8,737  40,610  49,347  (23,935) 1990 9/28/1998
30 Light Street (O) Baltimore, MD —  —  12,101  1,008  —  13,109  13,109  (2,308) 2009 8/7/2015
300 Secured Gateway (O) Annapolis Junction, MD —  —  3,128  —  —  3,128  3,128  —  (7) 3/23/2010
300 Sentinel Drive (O) Annapolis Junction, MD —  1,517  59,165  2,569  1,517  61,734  63,251  (18,370) 2009 11/14/2003
302 Sentinel Drive (O) Annapolis Junction, MD —  2,648  29,687  2,293  2,648  31,980  34,628  (10,987) 2007 11/14/2003
304 Sentinel Drive (O) Annapolis Junction, MD —  3,411  24,917  4,875  3,411  29,792  33,203  (12,067) 2005 11/14/2003
306 Sentinel Drive (O) Annapolis Junction, MD —  3,260  22,592  3,303  3,260  25,895  29,155  (10,098) 2006 11/14/2003
308 Sentinel Drive (O) Annapolis Junction, MD —  1,422  26,208  2,354  1,422  28,562  29,984  (7,882) 2010 11/14/2003
310 Sentinel Way (O) Annapolis Junction, MD —  2,372  42,591  —  2,372  42,591  44,963  (6,103) 2016 11/14/2003
310 The Bridge Street (O) Huntsville, AL —  261  26,530  5,227  261  31,757  32,018  (12,236) 2009 8/9/2011
312 Sentinel Way (O) Annapolis Junction, MD —  3,138  27,797  —  3,138  27,797  30,935  (5,084) 2014 11/14/2003
314 Sentinel Way (O) Annapolis Junction, MD —  1,254  7,741  —  1,254  7,741  8,995  (1,480) 2008 11/14/2003
316 Sentinel Way (O) Annapolis Junction, MD —  2,748  38,156  193  2,748  38,349  41,097  (9,410) 2011 11/14/2003
318 Sentinel Way (O) Annapolis Junction, MD —  2,185  28,426  560  2,185  28,986  31,171  (11,482) 2005 11/14/2003
Initial Cost Gross Amounts Carried
At Close of Period
Property (Type) (1) Location Encumbrances (2) Land Building
and Land Improvements		 Costs Capitalized Subsequent to Acquisition Land Building
and Land Improvements		 Total
(3)		 Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5)
320 Sentinel Way (O) Annapolis Junction, MD —  2,067  21,623  127  2,067  21,750  23,817  (7,606) 2007 11/14/2003
322 Sentinel Way (O) Annapolis Junction, MD —  2,605  22,827  1,910  2,605  24,737  27,342  (9,329) 2006 11/14/2003
324 Sentinel Way (O) Annapolis Junction, MD —  1,656  23,018  6  1,656  23,024  24,680  (6,531) 2010 6/29/2006
4000 Market Street (O) Huntsville, AL 6,052  —  9,187  —  —  9,187  9,187  (626) 2018 3/23/2010
410 National Business Parkway (O) Annapolis Junction, MD —  1,831  23,257  2,259  1,831  25,516  27,347  (6,032) 2012 6/29/2006
4100 Market Street (O) Huntsville, AL 5,269  —  8,020  7  —  8,027  8,027  (506) 2019 3/23/2010
420 National Business Parkway (O) Annapolis Junction, MD —  2,370  29,534  148  2,370  29,682  32,052  (5,467) 2013 6/29/2006
430 National Business Parkway (O) Annapolis Junction, MD —  1,852  21,563  1,893  1,852  23,456  25,308  (5,746) 2011 6/29/2006
44408 Pecan Court (O) California, MD —  817  1,583  1,751  817  3,334  4,151  (1,983) 1986 3/24/2004
44414 Pecan Court (O) California, MD —  405  1,619  1,138  405  2,757  3,162  (1,686) 1986 3/24/2004
44417 Pecan Court (O) California, MD —  434  3,822  180  434  4,002  4,436  (2,195) 1989/2015 3/24/2004
44420 Pecan Court (O) California, MD —  344  890  291  344  1,181  1,525  (607) 1989 11/9/2004
44425 Pecan Court (O) California, MD —  1,309  3,506  2,394  1,309  5,900  7,209  (3,757) 1997 5/5/2004
45310 Abell House Lane (O) California, MD —  2,272  13,808  878  2,272  14,686  16,958  (3,888) 2011 8/30/2010
4600 River Road (O) College Park, MD —  —  24,032  —  —  24,032  24,032  (436) 2020 1/29/2008
46579 Expedition Drive (O) Lexington Park, MD —  1,406  5,796  2,874  1,406  8,670  10,076  (4,563) 2002 3/24/2004
46591 Expedition Drive (O) Lexington Park, MD —  1,200  7,199  3,408  1,200  10,607  11,807  (4,557) 2005 3/24/2004
4851 Stonecroft Boulevard (O) Chantilly, VA —  1,878  11,558  194  1,878  11,752  13,630  (5,001) 2004 8/14/2002
540 National Business Parkway (O) Annapolis Junction, MD —  2,035  31,249  41  2,035  31,290  33,325  (3,321) 2017 6/29/2006
5520 Research Park Drive (O) Catonsville, MD —  —  20,072  1,757  —  21,829  21,829  (7,078) 2009 4/4/2006
5522 Research Park Drive (O) Catonsville, MD —  —  4,550  855  —  5,405  5,405  (1,851) 2007 3/8/2006
560 National Business Parkway (O) Annapolis Junction, MD —  2,193  28,973  —  2,193  28,973  31,166  —  (7) 6/29/2006
5801 University Research Court (O) College Park, MD 11,120  —  17,431  144  —  17,575  17,575  (1,772) 2018 1/29/2008
5825 University Research Court (O) College Park, MD 19,552  —  22,771  1,678  —  24,449  24,449  (8,014) 2008 1/29/2008
5850 University Research Court (O) College Park, MD 20,686  —  31,906  894  —  32,800  32,800  (9,746) 2008 1/29/2008
6000 Redstone Gateway (O) Huntsville, AL —  —  8,550  —  —  8,550  8,550  (201) 2020 3/23/2010
610 Guardian Way (O) Annapolis Junction, MD —  7,636  49,873  —  7,636  49,873  57,509  (276) 2021 6/29/2006
6200 Redstone Gateway (O) Huntsville, AL —  —  14,067  —  —  14,067  14,067  —  (7) 3/23/2010
6700 Alexander Bell Drive (O) Columbia, MD —  1,755  7,019  9,541  1,755  16,560  18,315  (9,466) 1988 5/14/2001
6708 Alexander Bell Drive (O) Columbia, MD —  897  12,693  1,618  897  14,311  15,208  (4,956) 1988/2016 5/14/2001
6711 Columbia Gateway Drive (O) Columbia, MD —  2,683  23,239  2,258  2,683  25,497  28,180  (9,995) 2006-2007 9/28/2000
6716 Alexander Bell Drive (O) Columbia, MD —  1,242  4,969  4,672  1,242  9,641  10,883  (6,399) 1990 12/31/1998
6721 Columbia Gateway Drive (O) Columbia, MD —  1,753  34,090  7,318  1,753  41,408  43,161  (11,406) 2009 9/28/2000
6724 Alexander Bell Drive (O) Columbia, MD —  449  5,039  2,492  449  7,531  7,980  (4,042) 2001 5/14/2001
6731 Columbia Gateway Drive (O) Columbia, MD —  2,807  19,098  5,689  2,807  24,787  27,594  (14,085) 2002 3/29/2000
6740 Alexander Bell Drive (O) Columbia, MD —  1,424  4,209  757  1,424  4,966  6,390  (2,627) 1992 12/31/1998
6741 Columbia Gateway Drive (O) Columbia, MD —  675  1,711  176  675  1,887  2,562  (715) 2008 9/28/2000
Initial Cost Gross Amounts Carried
At Close of Period
Property (Type) (1) Location Encumbrances (2) Land Building
and Land Improvements		 Costs Capitalized Subsequent to Acquisition Land Building
and Land Improvements		 Total
(3)		 Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5)
6750 Alexander Bell Drive (O) Columbia, MD —  1,263  12,461  5,856  1,263  18,317  19,580  (11,133) 2001 12/31/1998
6760 Alexander Bell Drive (O) Columbia, MD —  890  3,561  3,915  890  7,476  8,366  (5,115) 1991 12/31/1998
6940 Columbia Gateway Drive (O) Columbia, MD —  3,545  9,916  9,227  3,545  19,143  22,688  (11,631) 1999 11/13/1998
6950 Columbia Gateway Drive (O) Columbia, MD —  3,596  28,312  3,223  3,596  31,535  35,131  (12,711) 1998/2019 10/22/1998
7000 Columbia Gateway Drive (O) Columbia, MD —  3,131  12,103  8,551  3,131  20,654  23,785  (10,921) 1999 5/31/2002
7000 Redstone Gateway (O) Huntsville, AL —  —  897  —  —  897  897  —  (7) 3/23/2010
7005 Columbia Gateway Drive (L) Columbia, MD —  3,036  747  —  3,036  747  3,783  —  (6) 6/26/2014
7015 Albert Einstein Drive (O) Columbia, MD —  2,058  6,093  3,560  2,058  9,653  11,711  (5,005) 1999 12/1/2005
7061 Columbia Gateway Drive (O) Columbia, MD —  729  3,094  2,884  729  5,978  6,707  (3,608) 2000 8/30/2001
7063 Columbia Gateway Drive (O) Columbia, MD —  902  3,684  3,470  902  7,154  8,056  (4,721) 2000 8/30/2001
7065 Columbia Gateway Drive (O) Columbia, MD —  919  3,763  3,145  919  6,908  7,827  (4,703) 2000 8/30/2001
7067 Columbia Gateway Drive (O) Columbia, MD —  1,829  11,823  6,683  1,829  18,506  20,335  (9,409) 2001 8/30/2001
7100 Redstone Gateway (O) Huntsville, AL —  —  12,975  —  —  12,975  12,975  (204) 2021 3/23/2010
7125 Columbia Gateway Drive (O) Columbia, MD —  20,487  49,844  24,637  20,487  74,481  94,968  (30,038) 1973/1999 6/29/2006
7130 Columbia Gateway Drive (O) Columbia, MD —  1,350  4,359  3,029  1,350  7,388  8,738  (4,101) 1989 9/19/2005
7134 Columbia Gateway Drive (O) Columbia, MD —  704  4,700  729  704  5,429  6,133  (1,988) 1990/2016 9/19/2005
7138 Columbia Gateway Drive (O) Columbia, MD —  1,104  3,518  2,963  1,104  6,481  7,585  (4,286) 1990 9/19/2005
7142 Columbia Gateway Drive (O) Columbia, MD —  1,342  7,148  2,771  1,342  9,919  11,261  (4,494) 1994/2018 9/19/2005
7150 Columbia Gateway Drive (O) Columbia, MD —  1,032  3,429  1,705  1,032  5,134  6,166  (1,938) 1991 9/19/2005
7150 Riverwood Drive (O) Columbia, MD —  1,821  4,388  1,953  1,821  6,341  8,162  (3,162) 2000 1/10/2007
7160 Riverwood Drive (O) Columbia, MD —  2,732  7,006  4,609  2,732  11,615  14,347  (5,300) 2000 1/10/2007
7170 Riverwood Drive (O) Columbia, MD —  1,283  3,096  2,387  1,283  5,483  6,766  (2,787) 2000 1/10/2007
7175 Riverwood Drive (O) Columbia, MD —  1,788  7,269  —  1,788  7,269  9,057  (1,479) 1996/2013 7/27/2005
7200 Redstone Gateway (O) Huntsville, AL —  —  8,348  81  —  8,429  8,429  (1,611) 2013 3/23/2010
7200 Riverwood Drive (O) Columbia, MD —  4,089  22,630  4,693  4,089  27,323  31,412  (13,365) 1986 10/13/1998
7205 Riverwood Drive (O) Columbia, MD —  1,367  21,419  —  1,367  21,419  22,786  (4,523) 2013 7/27/2005
7272 Park Circle Drive (O) Hanover, MD —  1,479  6,300  4,609  1,479  10,909  12,388  (5,971) 1991/1996 1/10/2007
7318 Parkway Drive (O) Hanover, MD —  972  3,888  1,647  972  5,535  6,507  (3,120) 1984 4/16/1999
7400 Redstone Gateway (O) Huntsville, AL —  —  9,223  75  —  9,298  9,298  (1,519) 2015 3/23/2010
7467 Ridge Road (O) Hanover, MD —  1,565  3,116  5,997  1,565  9,113  10,678  (4,585) 1990 4/28/1999
7500 Advanced Gateway (O) Huntsville, AL —  —  18,663  —  —  18,663  18,663  (734) 2020 3/23/2010
7600 Advanced Gateway (O) Huntsville, AL —  —  13,752  —  —  13,752  13,752  (482) 2020 3/23/2010
7740 Milestone Parkway (O) Hanover, MD 16,432  3,825  34,176  1,254  3,825  35,430  39,255  (10,226) 2009 7/2/2007
7770 Backlick Road (O) Springfield, VA —  6,387  78,891  1,528  6,387  80,419  86,806  (17,275) 2012 3/10/2010
7880 Milestone Parkway (O) Hanover, MD —  4,857  26,836  1,338  4,857  28,174  33,031  (4,132) 2015 9/17/2013
8000 Rideout Road (O) Huntsville, AL —  —  21,667  —  —  21,667  21,667  (53) 2021 (7) 3/23/2010
8200 Rideout Road (O) (8) Huntsville, AL —  —  16,890  —  —  16,890  16,890  —  (7) 3/23/2010
Initial Cost Gross Amounts Carried
At Close of Period
Property (Type) (1) Location Encumbrances (2) Land Building
and Land Improvements		 Costs Capitalized Subsequent to Acquisition Land Building
and Land Improvements		 Total
(3)		 Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5)
8300 Rideout Road (O) (8) Huntsville, AL —  —  18,301  —  —  18,301  18,301  —  (7) 3/23/2010
8600 Advanced Gateway (O) Huntsville, AL —  —  27,298  —  —  27,298  27,298  (711) 2020 3/23/2010
8621 Robert Fulton Drive (O) Columbia, MD —  2,317  12,642  6,191  2,317  18,833  21,150  (8,822) 2005-2006 6/10/2005
8661 Robert Fulton Drive (O) Columbia, MD —  1,510  3,764  3,302  1,510  7,066  8,576  (3,825) 2002 12/30/2003
8671 Robert Fulton Drive (O) Columbia, MD —  1,718  4,280  4,294  1,718  8,574  10,292  (5,066) 2002 12/30/2003
870 Elkridge Landing Road (O) Linthicum, MD —  2,003  9,442  10,464  2,003  19,906  21,909  (12,706) 1981 8/3/2001
8800 Redstone Gateway (O) Huntsville, AL 11,679  —  18,465  —  —  18,465  18,465  (974) 2019 3/23/2010
891 Elkridge Landing Road (O) Linthicum, MD —  1,165  4,772  3,844  1,165  8,616  9,781  (5,472) 1984 7/2/2001
901 Elkridge Landing Road (O) Linthicum, MD —  1,156  4,437  6,034  1,156  10,471  11,627  (5,115) 1984 7/2/2001
911 Elkridge Landing Road (O) Linthicum, MD —  1,215  4,861  3,307  1,215  8,168  9,383  (5,116) 1985 4/30/1998
938 Elkridge Landing Road (O) Linthicum, MD —  922  4,748  1,534  922  6,282  7,204  (3,420) 1984 7/2/2001
939 Elkridge Landing Road (O) Linthicum, MD —  939  3,756  4,470  939  8,226  9,165  (6,064) 1983 4/30/1998
9651 Hornbaker Road (D) (9) Manassas, VA —  6,050  250,407  17,785  6,050  268,192  274,242  (82,385) 2010 9/14/2010
Arundel Preserve (L) Hanover, MD —  13,352  9,717  —  13,352  9,717  23,069  —  (6) 7/2/2007
Canton Crossing Land (L) Baltimore, MD —  17,285  8,409  227  17,285  8,636  25,921  —  (6) 10/27/2009
Canton Crossing Util Distr Ctr (O) Baltimore, MD —  6,100  10,450  1,689  6,100  12,139  18,239  (6,887) 2006 10/27/2009
Columbia Gateway - Southridge (L) Columbia, MD —  6,387  3,722  —  6,387  3,722  10,109  —  (6) 9/20/2004
Dahlgren Technology Center (L) Dahlgren, VA —  978  178  —  978  178  1,156  —  (6) 3/16/2005
Expedition VII (O) Lexington Park, MD —  705  7,208  —  705  7,208  7,913  —  (7) 3/24/2004
IN 1 (O) Northern Virginia —  1,815  16,017  —  1,815  16,017  17,832  (1,136) 2019 8/31/2016
IN 2 (O) Northern Virginia —  2,627  28,936  —  2,627  28,936  31,563  (1,804) 2019 8/31/2016
M Square Research Park (L) College Park, MD —  —  2,417  —  —  2,417  2,417  —  (6) 1/29/2008
MR Land (L) Northern Virginia —  9,038  554  —  9,038  554  9,592  —  (6) 11/8/2018
National Business Park North (L) Annapolis Junction, MD —  18,232  36,875  —  18,232  36,875  55,107  —  (6) 6/29/2006
North Gate Business Park (L) Aberdeen, MD —  1,755  5  —  1,755  5  1,760  —  (6) 9/14/2007
NoVA Office A (O) (8) Chantilly, VA —  2,096  46,849  —  2,096  46,849  48,945  (8,096) 2015 7/18/2002
NoVA Office B (O) (8) Chantilly, VA —  739  38,376  —  739  38,376  39,115  (4,715) 2016 7/18/2002
NoVA Office C (O) (8) Chantilly, VA —  7,751  78,907  —  7,751  78,907  86,658  (477) 2021 7/18/2002
NoVA Office D (O) (8) Chantilly, VA —  6,587  40,559  —  6,587  40,559  47,146  (4,466) 2017 7/2/2013
Oak Grove A (O) Northern Virginia —  12,866  34,814  —  12,866  34,814  47,680  (1,358) 2020 11/1/2018
Oak Grove B (O) Northern Virginia —  12,866  41,083  —  12,866  41,083  53,949  (1,832) 2019 11/1/2018
Oak Grove C (O) Northern Virginia —  9,491  64,671  —  9,491  64,671  74,162  —  (7) 11/1/2018
Oak Grove Phase II (L) Northern Virginia —  13,992  13,820  —  13,992  13,820  27,812  —  (6) 11/1/2018
Old Annapolis Road (O) Columbia, MD —  1,637  5,500  6,755  1,637  12,255  13,892  (5,362) 1974/1985 12/14/2000
P2 A (O) Northern Virginia —  16,853  40,132  —  16,853  40,132  56,985  (1,739) 2020 5/2/2019
P2 B (O) Northern Virginia —  22,839  36,362  —  22,839  36,362  59,201  (1,194) 2020 5/2/2019
P2 C (O) Northern Virginia —  14,869  31,482  —  14,869  31,482  46,351  (828) 2020 5/2/2019
Initial Cost Gross Amounts Carried
At Close of Period
Property (Type) (1) Location Encumbrances (2) Land Building
and Land Improvements		 Costs Capitalized Subsequent to Acquisition Land Building
and Land Improvements		 Total
(3)		 Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5)
Patriot Ridge (L) Springfield, VA —  18,517  14,573  —  18,517  14,573  33,090  —  (6) 3/10/2010
Project EL (O) Confidential-USA —  7,430  45,226  —  7,430  45,226  52,656  (552) 2021 1/20/2006
Project EX (O) (10) Confidential-USA —  13,010  19,097  —  13,010  19,097  32,107  (1,174) 2018 7/16/2008
PS A (O) Northern Virginia —  4,078  2,200  —  4,078  2,200  6,278  —  (7) 1/27/2005
PS B (O) Northern Virginia —  3,468  1,940  —  3,468  1,940  5,408  —  (7) 1/27/2005
Redstone Gateway (L) Huntsville, AL —  —  29,937  —  —  29,937  29,937  —  (6) 3/23/2010
Sentry Gateway - T (O) San Antonio, TX —  14,020  38,804  13  14,020  38,817  52,837  (14,443) 1982/2008 3/30/2005
Sentry Gateway - V (O) San Antonio, TX —  —  1,066  —  —  1,066  1,066  (348) 2007 3/30/2005
Sentry Gateway - W (O) San Antonio, TX —  —  1,884  71  —  1,955  1,955  (599) 2009 3/30/2005
Sentry Gateway - X (O) San Antonio, TX —  1,964  21,178  —  1,964  21,178  23,142  (5,905) 2010 1/20/2006
Sentry Gateway - Y (O) San Antonio, TX —  1,964  21,298  —  1,964  21,298  23,262  (5,940) 2010 1/20/2006
Sentry Gateway - Z (O) San Antonio, TX —  1,964  30,573  —  1,964  30,573  32,537  (5,203) 2015 6/14/2005
SP Manassas (L) Manassas, VA —  8,156  300  —  8,156  300  8,456  —  (6) 7/24/2019
Westfields - Park Center (L) Chantilly, VA —  8,667  3,155  —  8,667  3,155  11,822  —  (6) 7/2/2013
Other Developments, including
   intercompany eliminations (V)		 Various —  —  506  259  —  765  765  (115) Various Various
$ 121,425  $ 720,485  $ 3,635,390  $ 603,834  $ 720,485  $ 4,239,224  $ 4,959,709  $ (1,234,908)

(1)A legend for the Property Type follows: (O) = Office or Data Center Shell Property; (L) = Land held or pre-development; (D) = Wholesale Data Center; and (V) = Various.
(2)Excludes our Revolving Credit Facility of $76.0 million, term loan facilities of $299.4 million, unsecured senior notes of $1.8 billion, unsecured notes payable of $753,000, and deferred financing costs, net of premiums, on the remaining loans of $798,000.
(3)The aggregate cost of these assets for Federal income tax purposes was approximately $3.7 billion as of December 31, 2021.
(4)The estimated lives over which depreciation is recognized follow: Building and land improvements: 10-40 years; and tenant improvements: related lease terms.
(5)The acquisition date of multi-parcel properties reflects the date of the earliest parcel acquisition. The acquisition date of properties owned through real estate joint ventures reflects the date of the formation of the joint venture.
(6)Held as of December 31, 2021.
(7)Under development as of December 31, 2021.
(8)The carrying amounts of these properties exclude allocated costs of the garage being constructed to support the properties.
(9)Classified as held for sale as of December 31, 2021.
(10)This property represents land under a long-term contract.
The following table summarizes our changes in cost of properties for the years ended December 31, 2021, 2020 and 2019 (in thousands):
2021 2020 2019
Beginning balance $ 4,686,802  $ 4,348,006  $ 4,148,529 
Improvements and other additions 342,684  405,940  480,418 
Sales (1) (103,097) (65,475) (242,497)
Impairments —  (1,530) (329)
Other dispositions (4,511) (139) (340)
Reclassification from (to) right-of-use asset 37,831  —  (37,775)
Ending balance $ 4,959,709  $ 4,686,802  $ 4,348,006 
The following table summarizes our changes in accumulated depreciation for the same time periods (in thousands):
2021 2020 2019
Beginning balance $ 1,124,253  $ 1,007,120  $ 897,903 
Depreciation expense 130,604  119,377  117,973 
Sales (1) (15,438) (2,105) (8,416)
Other dispositions (4,511) (139) (340)
Ending balance $ 1,234,908  $ 1,124,253  $ 1,007,120 

(1)Includes our sale, through a series of transactions, of ownership interests in data center shells through newly-formed unconsolidated real estate joint ventures, as described in Note 4 to our consolidated financial statements.