Annual report pursuant to Section 13 and 15(d)

Schedule III - Real Estate and Accumulated Depreciation

v3.24.0.1
Schedule III - Real Estate and Accumulated Depreciation
 12 Months Ended
Dec. 31, 2023
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 $ —  $ 6,720  $ 31,215  $ 27,021  $ 6,720  $ 58,236  $ 64,956  $ (36,309) 1973/2011 8/7/2015
100 Secured Gateway (O) Huntsville, AL —  —  71,174  52  —  71,226  71,226  (5,910) 2020 3/23/2010
1000 Redstone Gateway (O) Huntsville, AL 8,461  —  20,533  217  —  20,750  20,750  (5,566) 2013 3/23/2010
1100 Redstone Gateway (O) Huntsville, AL 9,163  —  19,593  2,929  —  22,522  22,522  (4,956) 2014 3/23/2010
114 National Business Parkway (O) Annapolis Junction, MD —  364  3,109  427  364  3,536  3,900  (1,883) 2002 6/30/2000
1200 Redstone Gateway (O) Huntsville, AL 10,563  —  22,389  9,493  —  31,882  31,882  (6,195) 2013 3/23/2010
1201 M Street SE (O) Washington, DC —  —  49,775  10,883  —  60,658  60,658  (25,428) 2001 9/28/2010
1201 Winterson Road (O) Linthicum, MD —  2,130  17,207  937  2,130  18,144  20,274  (6,857) 1985/2017 4/30/1998
1220 12th Street SE (O) Washington, DC —  —  42,464  11,714  —  54,178  54,178  (23,306) 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  6,520  1,906  14,143  16,049  (9,286) 1990 9/28/1998
132 National Business Parkway (O) Annapolis Junction, MD —  2,917  12,259  4,995  2,917  17,254  20,171  (11,842) 2000 5/28/1999
133 National Business Parkway (O) Annapolis Junction, MD —  2,517  10,068  6,842  2,517  16,910  19,427  (11,967) 1997 9/28/1998
134 National Business Parkway (O) Annapolis Junction, MD —  3,684  7,517  5,973  3,684  13,490  17,174  (9,640) 1999 11/13/1998
1340 Ashton Road (O) Hanover, MD —  905  3,620  2,631  905  6,251  7,156  (3,861) 1989 4/28/1999
13450 Sunrise Valley Drive (O) Herndon, VA —  1,386  5,576  5,076  1,386  10,652  12,038  (7,417) 1998 7/25/2003
13454 Sunrise Valley Drive (O) Herndon, VA —  2,847  11,986  12,997  2,847  24,983  27,830  (14,469) 1998 7/25/2003
135 National Business Parkway (O) Annapolis Junction, MD —  2,484  9,750  7,296  2,484  17,046  19,530  (12,106) 1998 12/30/1998
1362 Mellon Road (O) Hanover, MD —  950  3,864  3,031  950  6,895  7,845  (1,898) 2006 2/10/2006
13857 McLearen Road (O) Herndon, VA —  3,507  30,177  5,911  3,507  36,088  39,595  (16,023) 2007 7/11/2012
140 National Business Parkway (O) Annapolis Junction, MD —  3,407  24,167  2,975  3,407  27,142  30,549  (13,110) 2003 12/31/2003
141 National Business Parkway (O) Annapolis Junction, MD —  2,398  9,538  4,844  2,398  14,382  16,780  (10,511) 1990 9/28/1998
14280 Park Meadow Drive (O) Chantilly, VA —  3,731  15,953  5,641  3,731  21,594  25,325  (12,342) 1999 9/29/2004
1460 Dorsey Road (L) Hanover, MD —  1,577  187  —  1,577  187  1,764  —  (6) 2/28/2006
14840 Conference Center Drive (O) Chantilly, VA —  1,572  8,175  5,833  1,572  14,008  15,580  (8,945) 2000 7/25/2003
14850 Conference Center Drive (O) Chantilly, VA —  1,615  8,358  7,740  1,615  16,098  17,713  (8,803) 2000 7/25/2003
14900 Conference Center Drive (O) Chantilly, VA —  3,436  14,402  10,459  3,436  24,861  28,297  (15,682) 1999 7/25/2003
1501 South Clinton Street (O) Baltimore, MD —  13,137  20,753  46,956  13,137  67,709  80,846  (38,074) 2006 10/27/2009
15049 Conference Center Drive (O) Chantilly, VA —  4,415  20,365  18,213  4,415  38,578  42,993  (24,412) 1997 8/14/2002
15059 Conference Center Drive (O) Chantilly, VA —  5,753  13,615  9,602  5,753  23,217  28,970  (12,086) 2000 8/14/2002
1550 West Nursery Road (O) Linthicum, MD —  14,071  16,930  —  14,071  16,930  31,001  (7,415) 2009 10/28/2009
1560 West Nursery Road (O) Linthicum, MD —  1,441  113  —  1,441  113  1,554  (27) 2014 10/28/2009
1610 West Nursery Road (O) Linthicum, MD —  259  246  —  259  246  505  (42) 2016 4/30/1998
1616 West Nursery Road (O) Linthicum, MD —  393  3,323  75  393  3,398  3,791  (539) 2017 4/30/1998
1622 West Nursery Road (O) Linthicum, MD —  393  2,542  —  393  2,542  2,935  (436) 2016 4/30/1998
16442 Commerce Drive (O) Dahlgren, VA —  613  2,582  1,142  613  3,724  4,337  (2,275) 2002 12/21/2004
16480 Commerce Drive (O) Dahlgren, VA —  1,856  7,425  2,878  1,856  10,303  12,159  (5,623) 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  1,251  522  3,341  3,863  (1,794) 2002 12/21/2004
16539 Commerce Drive (O) Dahlgren, VA —  688  2,860  2,345  688  5,205  5,893  (3,316) 1990 12/21/2004
16541 Commerce Drive (O) Dahlgren, VA —  773  3,094  2,715  773  5,809  6,582  (3,540) 1996 12/21/2004
16543 Commerce Drive (O) Dahlgren, VA —  436  1,742  907  436  2,649  3,085  (1,543) 2002 12/21/2004
1751 Pinnacle Drive (O) McLean, VA —  4,762  26,046  33,008  4,762  59,054  63,816  (48,466) 1989/1995 9/23/2004
1753 Pinnacle Drive (O) McLean, VA —  3,729  21,500  27,446  3,729  48,946  52,675  (33,423) 1976/2004 9/23/2004
206 Research Boulevard (O) Aberdeen, MD —  —  —  —  —  —  —  —  2012 9/14/2007
209 Research Boulevard (O) Aberdeen, MD —  134  1,711  842  134  2,553  2,687  (874) 2010 9/14/2007
210 Research Boulevard (O) Aberdeen, MD —  113  1,402  539  113  1,941  2,054  (710) 2010 9/14/2007
2100 L Street (O) Washington, DC —  41,935  71,067  —  41,935  71,067  113,002  (6,645) 2020 8/11/2015
2100 Rideout Road (O) Huntsville, AL —  —  7,336  3,256  —  10,592  10,592  (3,248) 2016 3/23/2010
22289 Exploration Drive (O) Lexington Park, MD —  1,422  5,719  2,379  1,422  8,098  9,520  (4,804) 2000 3/24/2004
22299 Exploration Drive (O) Lexington Park, MD —  1,278  5,791  3,085  1,278  8,876  10,154  (5,765) 1998 3/24/2004
22300 Exploration Drive (O) Lexington Park, MD —  1,094  5,038  3,060  1,094  8,098  9,192  (5,054) 1997 11/9/2004
22309 Exploration Drive (O) Lexington Park, MD —  2,160  10,419  8,179  2,160  18,598  20,758  (10,400) 1984/1997 3/24/2004
23535 Cottonwood Parkway (O) California, MD —  692  3,051  648  692  3,699  4,391  (2,524) 1984 3/24/2004
250 W Pratt St (O) Baltimore, MD —  4,704  21,487  21,784  4,704  43,271  47,975  (25,472) 1985 3/19/2015
2600 Park Tower Drive (O) Vienna, VA —  20,284  34,443  8,431  20,284  42,874  63,158  (11,121) 1999 4/15/2015
2691 Technology Drive (O) Annapolis Junction, MD —  2,098  17,334  9,191  2,098  26,525  28,623  (13,995) 2005 5/26/2000
2701 Technology Drive (O) Annapolis Junction, MD —  1,737  15,266  7,366  1,737  22,632  24,369  (14,744) 2001 5/26/2000
2711 Technology Drive (O) Annapolis Junction, MD —  2,251  21,611  4,509  2,251  26,120  28,371  (16,956) 2002 11/13/2000
2720 Technology Drive (O) Annapolis Junction, MD —  3,863  29,272  3,227  3,863  32,499  36,362  (16,331) 2004 1/31/2002
2721 Technology Drive (O) Annapolis Junction, MD —  4,611  14,597  3,836  4,611  18,433  23,044  (12,025) 2000 10/21/1999
2730 Hercules Road (O) Annapolis Junction, MD —  8,737  31,612  9,569  8,737  41,181  49,918  (26,409) 1990 9/28/1998
30 Light Street (O) Baltimore, MD —  —  2,501  625  —  3,126  3,126  (3,084) 2009 8/7/2015
300 Secured Gateway (O) Huntsville, AL —  —  63,500  —  —  63,500  63,500  (379) 2023 3/23/2010
300 Sentinel Drive (O) Annapolis Junction, MD —  1,517  59,165  2,590  1,517  61,755  63,272  (22,195) 2009 11/14/2003
302 Sentinel Drive (O) Annapolis Junction, MD —  2,648  29,687  6,540  2,648  36,227  38,875  (13,417) 2007 11/14/2003
304 Sentinel Drive (O) Annapolis Junction, MD —  3,411  24,917  5,335  3,411  30,252  33,663  (14,610) 2005 11/14/2003
306 Sentinel Drive (O) Annapolis Junction, MD —  3,260  22,592  3,755  3,260  26,347  29,607  (12,080) 2006 11/14/2003
308 Sentinel Drive (O) Annapolis Junction, MD —  1,422  26,208  2,365  1,422  28,573  29,995  (9,641) 2010 11/14/2003
310 Sentinel Way (O) Annapolis Junction, MD —  2,372  50,677  716  2,372  51,393  53,765  (8,291) 2016 11/14/2003
310 The Bridge Street (O) Huntsville, AL —  261  26,530  6,406  261  32,936  33,197  (14,449) 2009 8/9/2011
312 Sentinel Way (O) Annapolis Junction, MD —  3,138  27,797  —  3,138  27,797  30,935  (6,474) 2014 11/14/2003
314 Sentinel Way (O) Annapolis Junction, MD —  1,254  7,741  —  1,254  7,741  8,995  (1,947) 2008 11/14/2003
316 Sentinel Way (O) Annapolis Junction, MD —  2,748  38,156  298  2,748  38,454  41,202  (11,361) 2011 11/14/2003
318 Sentinel Way (O) Annapolis Junction, MD —  2,185  28,426  562  2,185  28,988  31,173  (13,016) 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  148  2,067  21,771  23,838  (8,753) 2007 11/14/2003
322 Sentinel Way (O) Annapolis Junction, MD —  2,605  22,827  1,900  2,605  24,727  27,332  (10,851) 2006 11/14/2003
324 Sentinel Way (O) Annapolis Junction, MD —  1,656  23,018  61  1,656  23,079  24,735  (7,690) 2010 6/29/2006
4000 Market Street (O) Huntsville, AL 5,914  —  9,198  1,955  —  11,153  11,153  (1,231) 2018 3/23/2010
410 National Business Parkway (O) Annapolis Junction, MD —  1,831  23,257  2,259  1,831  25,516  27,347  (8,066) 2012 6/29/2006
4100 Market Street (O) Huntsville, AL 5,148  —  8,046  7  —  8,053  8,053  (913) 2019 3/23/2010
420 National Business Parkway (O) Annapolis Junction, MD —  2,370  31,397  3,199  2,370  34,596  36,966  (7,049) 2013 6/29/2006
430 National Business Parkway (O) Annapolis Junction, MD —  1,852  21,563  3,118  1,852  24,681  26,533  (7,560) 2011 6/29/2006
44408 Pecan Court (O) California, MD —  817  1,583  1,861  817  3,444  4,261  (2,432) 1986 3/24/2004
44414 Pecan Court (O) California, MD —  405  1,619  1,229  405  2,848  3,253  (2,015) 1986 3/24/2004
44417 Pecan Court (O) California, MD —  434  3,822  295  434  4,117  4,551  (2,576) 1989/2015 3/24/2004
44420 Pecan Court (O) California, MD —  344  890  329  344  1,219  1,563  (729) 1989 11/9/2004
44425 Pecan Court (O) California, MD —  1,309  3,506  2,694  1,309  6,200  7,509  (4,310) 1997 5/5/2004
45310 Abell House Lane (O) California, MD —  2,272  13,808  1,812  2,272  15,620  17,892  (5,025) 2011 8/30/2010
4600 River Road (O) College Park, MD —  —  26,255  —  —  26,255  26,255  (1,706) 2020 1/29/2008
46579 Expedition Drive (O) Lexington Park, MD —  1,406  5,796  2,987  1,406  8,783  10,189  (5,214) 2002 3/24/2004
46591 Expedition Drive (O) Lexington Park, MD —  1,200  7,199  4,727  1,200  11,926  13,126  (5,899) 2005 3/24/2004
4851 Stonecroft Boulevard (O) Chantilly, VA —  1,878  11,558  483  1,878  12,041  13,919  (5,618) 2004 8/14/2002
5300 Redstone Gateway (O) Huntsville, AL —  —  17,350  —  —  17,350  17,350  —  (7) 3/23/2010
540 National Business Parkway (O) Annapolis Junction, MD —  2,035  35,545  41  2,035  35,586  37,621  (5,003) 2017 6/29/2006
550 National Business Parkway (O) Annapolis Junction, MD —  2,678  43,521  —  2,678  43,521  46,199  (98) 2023 6/29/2006
5520 Research Park Drive (O) Catonsville, MD —  —  20,072  2,356  —  22,428  22,428  (8,416) 2009 4/4/2006
5522 Research Park Drive (O) Catonsville, MD —  —  4,550  883  —  5,433  5,433  (2,249) 2007 3/8/2006
560 National Business Parkway (O) Annapolis Junction, MD —  2,193  55,079  —  2,193  55,079  57,272  (1,635) 2022 6/29/2006
5801 University Research Court (O) College Park, MD 10,640  —  17,431  162  —  17,593  17,593  (2,726) 2018 1/29/2008
5825 University Research Court (O) College Park, MD 18,580  —  22,771  2,874  —  25,645  25,645  (9,925) 2008 1/29/2008
5850 University Research Court (O) College Park, MD 19,657  —  31,906  1,112  —  33,018  33,018  (11,519) 2008 1/29/2008
6000 Redstone Gateway (O) Huntsville, AL —  —  8,542  17  —  8,559  8,559  (633) 2020 3/23/2010
610 Guardian Way (O) Annapolis Junction, MD —  7,636  53,682  —  7,636  53,682  61,318  (2,915) 2021 6/29/2006
6200 Redstone Gateway (O) Huntsville, AL —  —  50,086  —  —  50,086  50,086  (922) 2022 3/23/2010
6700 Alexander Bell Drive (O) Columbia, MD —  1,755  7,019  10,647  1,755  17,666  19,421  (11,013) 1988 5/14/2001
6708 Alexander Bell Drive (O) Columbia, MD —  897  12,693  1,618  897  14,311  15,208  (5,520) 1988/2016 5/14/2001
6711 Columbia Gateway Drive (O) Columbia, MD —  2,683  23,239  3,243  2,683  26,482  29,165  (11,617) 2006-2007 9/28/2000
6716 Alexander Bell Drive (O) Columbia, MD —  1,242  4,969  7,391  1,242  12,360  13,602  (7,078) 1990 12/31/1998
6721 Columbia Gateway Drive (O) Columbia, MD —  1,753  34,090  9,251  1,753  43,341  45,094  (15,125) 2009 9/28/2000
6724 Alexander Bell Drive (O) Columbia, MD —  449  5,039  2,680  449  7,719  8,168  (4,620) 2001 5/14/2001
6731 Columbia Gateway Drive (O) Columbia, MD —  2,807  19,098  6,920  2,807  26,018  28,825  (15,938) 2002 3/29/2000
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)
6740 Alexander Bell Drive (O) Columbia, MD —  1,424  4,209  9,685  1,424  13,894  15,318  (3,397) 1992 12/31/1998
6741 Columbia Gateway Drive (O) Columbia, MD —  675  1,711  179  675  1,890  2,565  (807) 2008 9/28/2000
6750 Alexander Bell Drive (O) Columbia, MD —  1,263  12,461  6,070  1,263  18,531  19,794  (12,322) 2001 12/31/1998
6760 Alexander Bell Drive (O) Columbia, MD —  890  3,561  3,946  890  7,507  8,397  (5,576) 1991 12/31/1998
6940 Columbia Gateway Drive (O) Columbia, MD —  3,545  9,916  12,806  3,545  22,722  26,267  (13,989) 1999 11/13/1998
6950 Columbia Gateway Drive (O) Columbia, MD —  3,596  28,278  3,223  3,596  31,501  35,097  (14,171) 1998/2019 10/22/1998
7000 Columbia Gateway Drive (O) Columbia, MD —  3,131  12,103  10,509  3,131  22,612  25,743  (13,223) 1999 5/31/2002
7000 Redstone Gateway (O) Huntsville, AL —  —  8,900  —  —  8,900  8,900  (147) 2022 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  (5,853) 1999 12/1/2005
7061 Columbia Gateway Drive (O) Columbia, MD —  729  3,094  2,907  729  6,001  6,730  (3,964) 2000 8/30/2001
7063 Columbia Gateway Drive (O) Columbia, MD —  902  3,684  3,707  902  7,391  8,293  (5,139) 2000 8/30/2001
7065 Columbia Gateway Drive (O) Columbia, MD —  919  3,763  3,302  919  7,065  7,984  (4,991) 2000 8/30/2001
7067 Columbia Gateway Drive (O) Columbia, MD —  1,829  11,823  9,177  1,829  21,000  22,829  (11,144) 2001 8/30/2001
7100 Redstone Gateway (O) Huntsville, AL —  —  12,989  —  —  12,989  12,989  (839) 2021 3/23/2010
7125 Columbia Gateway Drive (O) Columbia, MD —  20,487  49,926  29,466  20,487  79,392  99,879  (35,289) 1973/1999 6/29/2006
7130 Columbia Gateway Drive (O) Columbia, MD —  1,350  4,359  3,167  1,350  7,526  8,876  (4,626) 1989 9/19/2005
7134 Columbia Gateway Drive (O) Columbia, MD —  704  4,700  817  704  5,517  6,221  (2,330) 1990/2016 9/19/2005
7138 Columbia Gateway Drive (O) Columbia, MD —  1,104  3,518  2,989  1,104  6,507  7,611  (4,725) 1990 9/19/2005
7142 Columbia Gateway Drive (O) Columbia, MD —  1,342  7,148  4,265  1,342  11,413  12,755  (5,145) 1994/2018 9/19/2005
7150 Columbia Gateway Drive (O) Columbia, MD —  1,032  3,429  1,659  1,032  5,088  6,120  (2,392) 1991 9/19/2005
7150 Riverwood Drive (O) Columbia, MD —  1,821  4,388  16,234  1,821  20,622  22,443  (3,599) 2000 1/10/2007
7160 Riverwood Drive (O) Columbia, MD —  2,732  7,006  4,609  2,732  11,615  14,347  (6,322) 2000 1/10/2007
7170 Riverwood Drive (O) Columbia, MD —  1,283  3,096  2,389  1,283  5,485  6,768  (3,181) 2000 1/10/2007
7175 Riverwood Drive (O) Columbia, MD —  1,788  7,269  —  1,788  7,269  9,057  (1,842) 1996/2013 7/27/2005
7200 Redstone Gateway (O) Huntsville, AL —  —  8,348  185  —  8,533  8,533  (2,048) 2013 3/23/2010
7200 Riverwood Drive (O) Columbia, MD —  4,089  22,630  5,332  4,089  27,962  32,051  (15,053) 1986 10/13/1998
7205 Riverwood Drive (O) Columbia, MD —  1,367  21,419  —  1,367  21,419  22,786  (5,593) 2013 7/27/2005
7272 Park Circle Drive (O) Hanover, MD —  1,479  6,300  4,618  1,479  10,918  12,397  (6,956) 1991/1996 1/10/2007
7318 Parkway Drive (O) Hanover, MD —  972  3,888  2,297  972  6,185  7,157  (3,590) 1984 4/16/1999
7400 Redstone Gateway (O) Huntsville, AL —  —  9,223  75  —  9,298  9,298  (1,993) 2015 3/23/2010
7467 Ridge Road (O) Hanover, MD —  1,565  3,116  7,657  1,565  10,773  12,338  (5,750) 1990 4/28/1999
7500 Advanced Gateway (O) Huntsville, AL —  —  18,665  —  —  18,665  18,665  (1,667) 2020 3/23/2010
7600 Advanced Gateway (O) Huntsville, AL —  —  13,752  —  —  13,752  13,752  (1,170) 2020 3/23/2010
7740 Milestone Parkway (O) Hanover, MD —  3,825  34,176  1,855  3,825  36,031  39,856  (12,142) 2009 7/2/2007
7770 Backlick Road (O) Springfield, VA —  6,387  78,892  1,747  6,387  80,639  87,026  (21,899) 2012 3/10/2010
7880 Milestone Parkway (O) Hanover, MD —  4,857  27,173  1,619  4,857  28,792  33,649  (6,037) 2015 9/17/2013
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)
8000 Rideout Road (O) Huntsville, AL —  —  28,155  49  —  28,204  28,204  (1,240) 2021 3/23/2010
8100 Rideout Road (O) Huntsville, AL —  —  29,681  —  —  29,681  29,681  —  (7) 3/23/2010
8200 Rideout Road (O) Huntsville, AL —  —  45,653  —  —  45,653  45,653  (1,556) 2022 3/23/2010
8300 Rideout Road (O) Huntsville, AL —  —  52,678  —  —  52,678  52,678  (1,803) 2022 3/23/2010
8600 Advanced Gateway (O) Huntsville, AL —  —  27,312  24  —  27,336  27,336  (2,079) 2020 3/23/2010
8621 Robert Fulton Drive (O) Columbia, MD —  2,317  12,642  8,084  2,317  20,726  23,043  (10,265) 2005-2006 6/10/2005
8661 Robert Fulton Drive (O) Columbia, MD —  1,510  3,764  3,379  1,510  7,143  8,653  (4,437) 2002 12/30/2003
8671 Robert Fulton Drive (O) Columbia, MD —  1,718  4,280  4,848  1,718  9,128  10,846  (5,796) 2002 12/30/2003
870 Elkridge Landing Road (O) Linthicum, MD —  2,003  9,442  10,464  2,003  19,906  21,909  (14,016) 1981 8/3/2001
8800 Redstone Gateway (O) Huntsville, AL 11,413  —  18,470  —  —  18,470  18,470  (1,900) 2019 3/23/2010
891 Elkridge Landing Road (O) Linthicum, MD —  1,165  4,772  4,192  1,165  8,964  10,129  (6,042) 1984 7/2/2001
901 Elkridge Landing Road (O) Linthicum, MD —  1,156  4,437  7,429  1,156  11,866  13,022  (6,397) 1984 7/2/2001
911 Elkridge Landing Road (O) Linthicum, MD —  1,215  4,861  3,383  1,215  8,244  9,459  (5,783) 1985 4/30/1998
938 Elkridge Landing Road (O) Linthicum, MD —  922  4,748  1,538  922  6,286  7,208  (3,816) 1984 7/2/2001
939 Elkridge Landing Road (O) Linthicum, MD —  939  3,756  6,229  939  9,985  10,924  (6,565) 1983 4/30/1998
Arundel Preserve (L) Hanover, MD —  13,352  9,888  —  13,352  9,888  23,240  —  (6) 7/2/2007
Canton Crossing Land (L) Baltimore, MD —  —  6,009  57  —  6,066  6,066  (57) (6) 10/27/2009
Canton Crossing Util Distr Ctr (O) Baltimore, MD —  2,866  7,271  1,976  2,866  9,247  12,113  (8,026) 2006 10/27/2009
Columbia Gateway - Southridge (L) Columbia, MD —  6,387  3,725  —  6,387  3,725  10,112  —  (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  8,366  —  705  8,366  9,071  (319) 2022 3/24/2004
M Square Research Park (L) College Park, MD —  —  3,352  —  —  3,352  3,352  —  (6) 1/29/2008
MP 3 (O) Northern Virginia —  9,038  993  —  9,038  993  10,031  —  (7) 11/8/2018
National Business Park North (L) Annapolis Junction, MD —  15,554  28,744  —  15,554  28,744  44,298  —  (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) Chantilly, VA —  2,096  46,849  —  2,096  46,849  48,945  (10,436) 2015 7/18/2002
NoVA Office B (O) Chantilly, VA —  739  38,376  —  739  38,376  39,115  (6,675) 2016 7/18/2002
NoVA Office C (O) Chantilly, VA —  7,751  84,815  —  7,751  84,815  92,566  (4,503) 2021 7/18/2002
NoVA Office D (O) Chantilly, VA —  6,587  40,559  —  6,587  40,559  47,146  (6,499) 2017 7/2/2013
Oak Grove A (O) Northern Virginia —  12,866  42,087  —  12,866  42,087  54,953  (3,279) 2020 11/1/2018
Oak Grove B (O) Northern Virginia —  12,866  41,621  —  12,866  41,621  54,487  (3,908) 2019 11/1/2018
Oak Grove C (O) Northern Virginia —  11,741  78,829  —  11,741  78,829  90,570  (3,323) 2022 11/1/2018
Oak Grove D (O) Northern Virginia —  11,741  77,097  —  11,741  77,097  88,838  (2,096) 2022 11/1/2018
Old Annapolis Road (O) Columbia, MD —  1,637  5,500  6,985  1,637  12,485  14,122  (6,432) 1974/1985 12/14/2000
Patriot Ridge (L) Springfield, VA —  18,517  14,616  —  18,517  14,616  33,133  —  (6) 3/10/2010
Project EL (O) Confidential-USA —  7,190  46,912  —  7,190  46,912  54,102  (2,878) 2021 1/20/2006
Project EX (O) Confidential-USA —  13,010  19,107  —  13,010  19,107  32,117  (2,225) 2018 7/16/2008
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)
PS A (O) Northern Virginia —  4,078  54,122  —  4,078  54,122  58,200  (512) 2023 1/27/2005
PS B (O) Northern Virginia —  3,468  45,377  —  3,468  45,377  48,845  (82) 2023 1/27/2005
Redstone Gateway (L) Huntsville, AL —  —  31,193  —  —  31,193  31,193  —  (6) 3/23/2010
Sentry Gateway - T (O) San Antonio, TX —  14,020  38,804  13  14,020  38,817  52,837  (16,384) 1982/2008 3/30/2005
Sentry Gateway - V (O) San Antonio, TX —  —  1,066  —  —  1,066  1,066  (401) 2007 3/30/2005
Sentry Gateway - W (O) San Antonio, TX —  —  1,884  71  —  1,955  1,955  (703) 2009 3/30/2005
Sentry Gateway - X (O) San Antonio, TX —  1,964  21,178  53  1,964  21,231  23,195  (6,978) 2010 1/20/2006
Sentry Gateway - Y (O) San Antonio, TX —  1,964  21,298  8  1,964  21,306  23,270  (7,007) 2010 1/20/2006
Sentry Gateway - Z (O) San Antonio, TX —  1,964  30,573  —  1,964  30,573  32,537  (6,733) 2015 6/14/2005
Southpoint Phase 2 Bldg A (O) Northern Virginia —  4,404  16,356  —  4,404  16,356  20,760  —  (7) 7/24/2019
Southpoint Phase 2 Bldg B (O) Northern Virginia —  3,752  1,398  —  3,752  1,398  5,150  —  (7) 7/24/2019
Westfields - Park Center (L) Chantilly, VA —  8,667  3,515  —  8,667  3,515  12,182  —  (6) 7/2/2013
Other Developments, including
   intercompany eliminations (V)		 Various —  —  1,140  258  —  1,398  1,398  (167) Various Various
$ 99,539  $ 570,610  $ 3,607,812  $ 725,418  $ 570,610  $ 4,333,230  $ 4,903,840  $ (1,400,162)
(1)A legend for the Property Type follows: (O) = Office or data center shell property; (L) = Land held or pre-development; and (V) = Various.
(2)Excludes our Revolving Credit Facility of $75.0 million, term loan facilities of $124.3 million, unsecured senior notes of $2.1 billion, unsecured notes payable of $430,000, and deferred financing costs, net of premiums, on the remaining loans of $331,000.
(3)The aggregate cost of these assets for federal income tax purposes was approximately $3.8 billion as of December 31, 2023.
(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, 2023.
(7)Under development as of December 31, 2023.
The following table summarizes our changes in cost of properties for the years ended December 31, 2023, 2022 and 2021 (in thousands):
2023 2022 2021
Beginning balance $ 4,986,537  $ 4,959,709  $ 4,686,802 
Improvements and other additions 333,081  350,702  342,684 
Sales (1) (162,981) (323,874) (103,097)
Impairments (2) (252,797) —  — 
Other dispositions —  —  (4,511)
Reclassification from right-of-use asset —  —  37,831 
Ending balance $ 4,903,840  $ 4,986,537  $ 4,959,709 
The following table summarizes our changes in accumulated depreciation for the same time periods (in thousands):
2023 2022 2021
Beginning balance $ 1,273,448  $ 1,234,908  $ 1,124,253 
Depreciation expense 132,728  124,803  130,604 
Sales (1) (6,014) (86,263) (15,438)
Other dispositions —  —  (4,511)
Ending balance $ 1,400,162  $ 1,273,448  $ 1,234,908 
(1)Includes sales of our wholesale data center and ownership interests in data center shells through newly-formed unconsolidated real estate joint ventures, as described in Note 4 to our consolidated financial statements.
(2)Includes impairment recognized on six operating properties and a parcel of land, as described in Note 4 to our consolidated financial statements.