Annual report pursuant to Section 13 and 15(d)

Schedule III - Real Estate and Accumulated Depreciation

v3.25.0.1
Schedule III - Real Estate and Accumulated Depreciation
 12 Months Ended
Dec. 31, 2024
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  $ 31,887  $ 6,720  $ 63,102  $ 69,822  $ (39,347) 1973/2011 8/7/2015
100 Secured Gateway (O) Huntsville, AL —  —  71,180  108  —  71,288  71,288  (7,700) 2020 3/23/2010
1000 Redstone Gateway (O) Huntsville, AL —  —  20,533  241  —  20,774  20,774  (6,092) 2013 3/23/2010
1100 Redstone Gateway (O) Huntsville, AL —  —  19,593  4,359  —  23,952  23,952  (5,701) 2014 3/23/2010
114 National Business Parkway (O) Annapolis Junction, MD —  364  3,109  427  364  3,536  3,900  (1,985) 2002 6/30/2000
1200 Redstone Gateway (O) Huntsville, AL —  —  22,389  11,794  —  34,183  34,183  (7,987) 2013 3/23/2010
1201 M Street SE (O) Washington, DC —  —  49,775  11,615  —  61,390  61,390  (27,471) 2001 9/28/2010
1201 Winterson Road (O) Linthicum, MD —  2,130  17,769  1,197  2,130  18,966  21,096  (7,305) 1985/2017 4/30/1998
1220 12th Street SE (O) Washington, DC —  —  42,464  11,996  —  54,460  54,460  (25,127) 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  6,876  1,906  14,499  16,405  (10,092) 1990 9/28/1998
132 National Business Parkway (O) Annapolis Junction, MD —  2,917  12,259  4,996  2,917  17,255  20,172  (12,210) 2000 5/28/1999
133 National Business Parkway (O) Annapolis Junction, MD —  2,517  10,068  7,034  2,517  17,102  19,619  (12,476) 1997 9/28/1998
134 National Business Parkway (O) Annapolis Junction, MD —  3,684  7,517  5,924  3,684  13,441  17,125  (10,100) 1999 11/13/1998
1340 Ashton Road (O) Hanover, MD —  905  3,620  2,743  905  6,363  7,268  (4,066) 1989 4/28/1999
13450 Sunrise Valley Drive (O) Herndon, VA —  1,386  5,576  8,433  1,386  14,009  15,395  (7,632) 1998 7/25/2003
13454 Sunrise Valley Drive (O) Herndon, VA —  2,847  11,986  14,962  2,847  26,948  29,795  (15,830) 1998 7/25/2003
135 National Business Parkway (O) Annapolis Junction, MD —  2,484  9,750  7,302  2,484  17,052  19,536  (12,646) 1998 12/30/1998
1362 Mellon Road (O) Hanover, MD —  950  3,864  3,389  950  7,253  8,203  (2,606) 2006 2/10/2006
13857 McLearen Road (O) Herndon, VA —  3,507  30,177  6,413  3,507  36,590  40,097  (17,042) 2007 7/11/2012
140 National Business Parkway (O) Annapolis Junction, MD —  3,407  24,167  2,995  3,407  27,162  30,569  (13,892) 2003 12/31/2003
141 National Business Parkway (O) Annapolis Junction, MD —  2,398  9,538  7,169  2,398  16,707  19,105  (10,822) 1990 9/28/1998
14280 Park Meadow Drive (O) Chantilly, VA —  3,731  15,953  7,395  3,731  23,348  27,079  (13,205) 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  5,813  1,572  13,988  15,560  (9,477) 2000 7/25/2003
14850 Conference Center Drive (O) Chantilly, VA —  1,615  8,358  8,355  1,615  16,713  18,328  (9,584) 2000 7/25/2003
14900 Conference Center Drive (O) Chantilly, VA —  3,436  14,402  10,714  3,436  25,116  28,552  (16,346) 1999 7/25/2003
1501 South Clinton Street (O) Baltimore, MD —  13,137  20,753  47,566  13,137  68,319  81,456  (40,781) 2006 10/27/2009
15049 Conference Center Drive (O) Chantilly, VA —  4,415  20,365  18,568  4,415  38,933  43,348  (26,087) 1997 8/14/2002
15059 Conference Center Drive (O) Chantilly, VA —  5,753  13,615  9,591  5,753  23,206  28,959  (13,122) 2000 8/14/2002
1550 West Nursery Road (O) Linthicum, MD —  14,071  16,930  —  14,071  16,930  31,001  (7,783) 2009 10/28/2009
1560 West Nursery Road (O) Linthicum, MD —  1,441  113  —  1,441  113  1,554  (30) 2014 10/28/2009
1610 West Nursery Road (O) Linthicum, MD —  259  246  —  259  246  505  (48) 2016 4/30/1998
1616 West Nursery Road (O) Linthicum, MD —  393  3,323  75  393  3,398  3,791  (629) 2017 4/30/1998
1622 West Nursery Road (O) Linthicum, MD —  393  2,542  —  393  2,542  2,935  (500) 2016 4/30/1998
16442 Commerce Drive (O) Dahlgren, VA —  613  2,582  1,143  613  3,725  4,338  (2,358) 2002 12/21/2004
16480 Commerce Drive (O) Dahlgren, VA —  1,856  7,425  3,736  1,856  11,161  13,017  (6,049) 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  1,674  522  3,764  4,286  (1,924) 2002 12/21/2004
16539 Commerce Drive (O) Dahlgren, VA —  688  2,860  2,481  688  5,341  6,029  (3,442) 1990 12/21/2004
16541 Commerce Drive (O) Dahlgren, VA —  773  3,094  2,715  773  5,809  6,582  (3,801) 1996 12/21/2004
16543 Commerce Drive (O) Dahlgren, VA —  436  1,742  906  436  2,648  3,084  (1,632) 2002 12/21/2004
1751 Pinnacle Drive (O) McLean, VA —  4,762  26,046  34,717  4,762  60,763  65,525  (50,069) 1989/1995 9/23/2004
1753 Pinnacle Drive (O) McLean, VA —  3,729  21,500  28,740  3,729  50,240  53,969  (35,257) 1976/2004 9/23/2004
206 Research Boulevard (O) Aberdeen, MD —  —  —  —  —  —  —  —  2012 9/14/2007
209 Research Boulevard (O) Aberdeen, MD —  134  1,711  895  134  2,606  2,740  (1,016) 2010 9/14/2007
210 Research Boulevard (O) Aberdeen, MD —  113  1,402  593  113  1,995  2,108  (813) 2010 9/14/2007
2100 L Street (O) Washington, DC —  41,935  74,965  —  41,935  74,965  116,900  (8,426) 2020 8/11/2015
2100 Rideout Road (O) Huntsville, AL —  —  7,336  3,583  —  10,919  10,919  (3,759) 2016 3/23/2010
22289 Exploration Drive (O) Lexington Park, MD —  1,422  5,719  2,657  1,422  8,376  9,798  (5,120) 2000 3/24/2004
22299 Exploration Drive (O) Lexington Park, MD —  1,278  5,791  3,085  1,278  8,876  10,154  (5,966) 1998 3/24/2004
22300 Exploration Drive (O) Lexington Park, MD —  1,094  5,038  3,061  1,094  8,099  9,193  (5,307) 1997 11/9/2004
22309 Exploration Drive (O) Lexington Park, MD —  2,160  10,419  12,011  2,160  22,430  24,590  (11,076) 1984/1997 3/24/2004
23535 Cottonwood Parkway (O) California, MD —  692  3,051  706  692  3,757  4,449  (2,690) 1984 3/24/2004
250 W Pratt St (O) Baltimore, MD —  4,704  21,487  23,603  4,704  45,090  49,794  (27,845) 1985 3/19/2015
2600 Park Tower Drive (O) Vienna, VA —  20,263  34,443  17,535  20,263  51,978  72,241  (13,133) 1999 4/15/2015
2691 Technology Drive (O) Annapolis Junction, MD —  2,098  17,334  9,191  2,098  26,525  28,623  (14,958) 2005 5/26/2000
2701 Technology Drive (O) Annapolis Junction, MD —  1,737  15,266  8,523  1,737  23,789  25,526  (15,503) 2001 5/26/2000
2711 Technology Drive (O) Annapolis Junction, MD —  2,251  21,611  7,198  2,251  28,809  31,060  (17,607) 2002 11/13/2000
2720 Technology Drive (O) Annapolis Junction, MD —  3,863  29,272  3,257  3,863  32,529  36,392  (17,427) 2004 1/31/2002
2721 Technology Drive (O) Annapolis Junction, MD —  4,611  14,597  5,706  4,611  20,303  24,914  (12,575) 2000 10/21/1999
2730 Hercules Road (O) Annapolis Junction, MD —  8,737  31,612  10,659  8,737  42,271  51,008  (27,592) 1990 9/28/1998
30 Light Street (O) Baltimore, MD —  —  2,501  762  —  3,263  3,263  (3,093) 2009 8/7/2015
300 Secured Gateway (O) Huntsville, AL —  —  64,356  32  —  64,388  64,388  (1,986) 2023 3/23/2010
300 Sentinel Drive (O) Annapolis Junction, MD —  1,517  59,165  3,702  1,517  62,867  64,384  (24,050) 2009 11/14/2003
302 Sentinel Drive (O) Annapolis Junction, MD —  2,648  29,687  8,015  2,648  37,702  40,350  (15,247) 2007 11/14/2003
304 Sentinel Drive (O) Annapolis Junction, MD —  3,411  24,917  5,353  3,411  30,270  33,681  (15,864) 2005 11/14/2003
306 Sentinel Drive (O) Annapolis Junction, MD —  3,260  22,592  3,901  3,260  26,493  29,753  (12,963) 2006 11/14/2003
308 Sentinel Drive (O) Annapolis Junction, MD —  1,422  26,208  2,365  1,422  28,573  29,995  (10,521) 2010 11/14/2003
310 Sentinel Way (O) Annapolis Junction, MD —  2,372  50,750  706  2,372  51,456  53,828  (9,550) 2016 11/14/2003
310 The Bridge Street (O) Huntsville, AL —  261  26,530  7,230  261  33,760  34,021  (15,607) 2009 8/9/2011
312 Sentinel Way (O) Annapolis Junction, MD —  3,138  27,797  —  3,138  27,797  30,935  (7,169) 2014 11/14/2003
314 Sentinel Way (O) Annapolis Junction, MD —  1,254  7,741  —  1,254  7,741  8,995  (2,180) 2008 11/14/2003
316 Sentinel Way (O) Annapolis Junction, MD —  2,748  38,156  279  2,748  38,435  41,183  (12,332) 2011 11/14/2003
318 Sentinel Way (O) Annapolis Junction, MD —  2,185  28,426  568  2,185  28,994  31,179  (13,784) 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  156  2,067  21,779  23,846  (9,301) 2007 11/14/2003
322 Sentinel Way (O) Annapolis Junction, MD —  2,605  22,827  1,901  2,605  24,728  27,333  (11,611) 2006 11/14/2003
324 Sentinel Way (O) Annapolis Junction, MD —  1,656  23,018  62  1,656  23,080  24,736  (8,271) 2010 6/29/2006
340th Trail (L) Van Meter, IA —  32,852  419  —  32,852  419  33,271  —  (6) 9/27/2024
3900 Rogers Road (O) San Antonio, TX —  2,932  14,101  —  2,932  14,101  17,033  (88) 2005 9/26/2024
400 National Business Parkway (O) Annapolis Junction, MD —  —  41,547  —  —  41,547  41,547  —  (7) 6/29/2006
4000 Market Street (O) Huntsville, AL 5,835  —  9,198  2,162  —  11,360  11,360  (1,666) 2018 3/23/2010
410 National Business Parkway (O) Annapolis Junction, MD —  1,831  23,257  2,997  1,831  26,254  28,085  (9,010) 2012 6/29/2006
4100 Market Street (O) Huntsville, AL 5,080  —  8,046  26  —  8,072  8,072  (1,118) 2019 3/23/2010
420 National Business Parkway (O) Annapolis Junction, MD —  2,370  31,607  4,364  2,370  35,971  38,341  (8,289) 2013 6/29/2006
430 National Business Parkway (O) Annapolis Junction, MD —  1,852  21,563  4,562  1,852  26,125  27,977  (8,672) 2011 6/29/2006
44408 Pecan Court (O) California, MD —  817  1,583  1,861  817  3,444  4,261  (2,577) 1986 3/24/2004
44414 Pecan Court (O) California, MD —  405  1,619  1,229  405  2,848  3,253  (2,161) 1986 3/24/2004
44417 Pecan Court (O) California, MD —  434  3,822  315  434  4,137  4,571  (2,774) 1989/2015 3/24/2004
44420 Pecan Court (O) California, MD —  344  890  418  344  1,308  1,652  (792) 1989 11/9/2004
44425 Pecan Court (O) California, MD —  1,309  3,506  2,697  1,309  6,203  7,512  (4,564) 1997 5/5/2004
45310 Abell House Lane (O) California, MD —  2,272  13,808  2,884  2,272  16,692  18,964  (5,819) 2011 8/30/2010
4600 River Road (O) College Park, MD —  —  27,338  123  —  27,461  27,461  (2,376) 2020 1/29/2008
46579 Expedition Drive (O) Lexington Park, MD —  1,406  5,796  3,016  1,406  8,812  10,218  (5,497) 2002 3/24/2004
46591 Expedition Drive (O) Lexington Park, MD —  1,200  7,199  5,164  1,200  12,363  13,563  (6,500) 2005 3/24/2004
4851 Stonecroft Boulevard (O) Chantilly, VA —  1,878  11,558  1,355  1,878  12,913  14,791  (5,991) 2004 8/14/2002
5300 Redstone Gateway (O) Huntsville, AL —  —  19,001  —  —  19,001  19,001  (392) 2024 3/23/2010
540 National Business Parkway (O) Annapolis Junction, MD —  2,035  35,639  41  2,035  35,680  37,715  (5,925) 2017 6/29/2006
550 National Business Parkway (O) Annapolis Junction, MD —  2,678  44,027  —  2,678  44,027  46,705  (1,298) 2023 6/29/2006
5520 Research Park Drive (O) Catonsville, MD —  —  20,072  2,376  —  22,448  22,448  (9,156) 2009 4/4/2006
5522 Research Park Drive (O) Catonsville, MD —  —  4,550  985  —  5,535  5,535  (2,425) 2007 3/8/2006
560 National Business Parkway (O) Annapolis Junction, MD —  2,193  55,484  —  2,193  55,484  57,677  (3,047) 2022 6/29/2006
5801 University Research Court (O) College Park, MD 10,400  —  17,431  162  —  17,593  17,593  (3,158) 2018 1/29/2008
5825 University Research Court (O) College Park, MD 18,067  —  22,771  3,675  —  26,446  26,446  (10,782) 2008 1/29/2008
5850 University Research Court (O) College Park, MD 19,114  —  31,906  1,112  —  33,018  33,018  (12,415) 2008 1/29/2008
6000 Redstone Gateway (O) Huntsville, AL —  —  8,542  35  —  8,577  8,577  (852) 2020 3/23/2010
610 Guardian Way (O) Annapolis Junction, MD —  7,636  54,053  —  7,636  54,053  61,689  (4,263) 2021 6/29/2006
6200 Redstone Gateway (O) Huntsville, AL —  —  51,343  —  —  51,343  51,343  (2,849) 2022 3/23/2010
6700 Alexander Bell Drive (O) Columbia, MD —  1,755  7,019  11,262  1,755  18,281  20,036  (11,758) 1988 5/14/2001
6708 Alexander Bell Drive (O) Columbia, MD —  897  12,693  1,624  897  14,317  15,214  (5,801) 1988/2016 5/14/2001
6711 Columbia Gateway Drive (O) Columbia, MD —  2,683  23,239  3,413  2,683  26,652  29,335  (12,411) 2006-2007 9/28/2000
6716 Alexander Bell Drive (O) Columbia, MD —  1,242  4,969  8,321  1,242  13,290  14,532  (7,669) 1990 12/31/1998
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)
6721 Columbia Gateway Drive (O) Columbia, MD —  1,753  34,090  14,624  1,753  48,714  50,467  (17,021) 2009 9/28/2000
6724 Alexander Bell Drive (O) Columbia, MD —  449  5,039  2,698  449  7,737  8,186  (4,923) 2001 5/14/2001
6731 Columbia Gateway Drive (O) Columbia, MD —  2,807  19,098  7,035  2,807  26,133  28,940  (16,920) 2002 3/29/2000
6740 Alexander Bell Drive (O) Columbia, MD —  1,424  4,209  10,544  1,424  14,753  16,177  (4,110) 1992 12/31/1998
6741 Columbia Gateway Drive (O) Columbia, MD —  675  1,711  535  675  2,246  2,921  (855) 2008 9/28/2000
6750 Alexander Bell Drive (O) Columbia, MD —  1,263  12,461  6,070  1,263  18,531  19,794  (12,881) 2001 12/31/1998
6760 Alexander Bell Drive (O) Columbia, MD —  890  3,561  4,253  890  7,814  8,704  (5,817) 1991 12/31/1998
6841 Benjamin Franklin Drive (O) Columbia, MD —  5,429  2,534  1,697  5,429  4,231  9,660  (567) 2008 3/15/2024
6940 Columbia Gateway Drive (O) Columbia, MD —  3,545  9,916  13,156  3,545  23,072  26,617  (15,179) 1999 11/13/1998
6950 Columbia Gateway Drive (O) Columbia, MD —  3,596  28,278  3,223  3,596  31,501  35,097  (14,899) 1998/2019 10/22/1998
7000 Columbia Gateway Drive (O) Columbia, MD —  3,131  12,103  10,516  3,131  22,619  25,750  (14,394) 1999 5/31/2002
7000 Redstone Gateway (O) Huntsville, AL —  —  10,036  30  —  10,066  10,066  (458) 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  (6,068) 1999 12/1/2005
7061 Columbia Gateway Drive (O) Columbia, MD —  729  3,094  2,902  729  5,996  6,725  (4,125) 2000 8/30/2001
7063 Columbia Gateway Drive (O) Columbia, MD —  902  3,684  3,707  902  7,391  8,293  (5,314) 2000 8/30/2001
7065 Columbia Gateway Drive (O) Columbia, MD —  919  3,763  4,017  919  7,780  8,699  (5,221) 2000 8/30/2001
7067 Columbia Gateway Drive (O) Columbia, MD —  1,829  11,823  10,077  1,829  21,900  23,729  (12,159) 2001 8/30/2001
7100 Redstone Gateway (O) Huntsville, AL —  —  12,983  17  —  13,000  13,000  (1,164) 2021 3/23/2010
7125 Columbia Gateway Drive (O) Columbia, MD —  20,487  49,926  34,620  20,487  84,546  105,033  (38,340) 1973/1999 6/29/2006
7130 Columbia Gateway Drive (O) Columbia, MD —  1,350  4,359  3,187  1,350  7,546  8,896  (4,927) 1989 9/19/2005
7134 Columbia Gateway Drive (O) Columbia, MD —  704  4,700  837  704  5,537  6,241  (2,503) 1990/2016 9/19/2005
7138 Columbia Gateway Drive (O) Columbia, MD —  1,104  3,518  3,067  1,104  6,585  7,689  (4,841) 1990 9/19/2005
7142 Columbia Gateway Drive (O) Columbia, MD —  1,342  7,148  4,236  1,342  11,384  12,726  (5,690) 1994/2018 9/19/2005
7150 Columbia Gateway Drive (O) Columbia, MD —  1,032  3,429  1,824  1,032  5,253  6,285  (2,620) 1991 9/19/2005
7150 Riverwood Drive (O) Columbia, MD —  1,821  4,388  16,232  1,821  20,620  22,441  (4,463) 2000 1/10/2007
7160 Riverwood Drive (O) Columbia, MD —  2,732  7,006  4,609  2,732  11,615  14,347  (6,810) 2000 1/10/2007
7170 Riverwood Drive (O) Columbia, MD —  1,283  3,096  2,624  1,283  5,720  7,003  (3,387) 2000 1/10/2007
7175 Riverwood Drive (O) Columbia, MD —  1,788  7,269  57  1,788  7,326  9,114  (2,031) 1996/2013 7/27/2005
7200 Redstone Gateway (O) Huntsville, AL —  —  8,348  206  —  8,554  8,554  (2,273) 2013 3/23/2010
7200 Riverwood Drive (O) Columbia, MD —  4,089  22,630  5,908  4,089  28,538  32,627  (15,880) 1986 10/13/1998
7205 Riverwood Drive (O) Columbia, MD —  1,367  21,419  345  1,367  21,764  23,131  (6,129) 2013 7/27/2005
7272 Park Circle Drive (O) Hanover, MD —  1,479  6,300  5,263  1,479  11,563  13,042  (7,203) 1991/1996 1/10/2007
7318 Parkway Drive (O) Hanover, MD —  972  3,888  2,313  972  6,201  7,173  (3,808) 1984 4/16/1999
7400 Redstone Gateway (O) Huntsville, AL —  —  9,223  93  —  9,316  9,316  (2,231) 2015 3/23/2010
7467 Ridge Road (O) Hanover, MD —  1,565  3,116  7,729  1,565  10,845  12,410  (6,398) 1990 4/28/1999
7500 Advanced Gateway (O) Huntsville, AL —  —  18,665  97  —  18,762  18,762  (2,138) 2020 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)
7600 Advanced Gateway (O) Huntsville, AL —  —  13,752  28  —  13,780  13,780  (1,514) 2020 3/23/2010
7740 Milestone Parkway (O) Hanover, MD —  3,825  34,176  2,055  3,825  36,231  40,056  (13,148) 2009 7/2/2007
7770 Backlick Road (O) Springfield, VA —  6,387  78,892  2,185  6,387  81,077  87,464  (24,179) 2012 3/10/2010
7880 Milestone Parkway (O) Hanover, MD —  4,857  27,166  1,675  4,857  28,841  33,698  (7,003) 2015 9/17/2013
8000 Rideout Road (O) Huntsville, AL —  —  28,157  203  —  28,360  28,360  (1,964) 2021 3/23/2010
8100 Rideout Road (O) Huntsville, AL —  —  35,591  3  —  35,594  35,594  (544) 2024 3/23/2010
8200 Rideout Road (O) Huntsville, AL —  —  45,903  3  —  45,906  45,906  (3,138) 2022 3/23/2010
8300 Rideout Road (O) Huntsville, AL —  —  52,633  6  —  52,639  52,639  (3,672) 2022 3/23/2010
8600 Advanced Gateway (O) Huntsville, AL —  —  27,314  59  —  27,373  27,373  (2,765) 2020 3/23/2010
8621 Robert Fulton Drive (O) Columbia, MD —  2,317  12,642  8,084  2,317  20,726  23,043  (11,072) 2005-2006 6/10/2005
8661 Robert Fulton Drive (O) Columbia, MD —  1,510  3,764  3,443  1,510  7,207  8,717  (4,749) 2002 12/30/2003
8671 Robert Fulton Drive (O) Columbia, MD —  1,718  4,280  4,848  1,718  9,128  10,846  (6,173) 2002 12/30/2003
870 Elkridge Landing Road (O) Linthicum, MD —  2,003  9,442  10,600  2,003  20,042  22,045  (14,579) 1981 8/3/2001
8800 Redstone Gateway (O) Huntsville, AL 11,260  —  18,470  12  —  18,482  18,482  (2,363) 2019 3/23/2010
891 Elkridge Landing Road (O) Linthicum, MD —  1,165  4,772  4,442  1,165  9,214  10,379  (6,534) 1984 7/2/2001
901 Elkridge Landing Road (O) Linthicum, MD —  1,156  4,437  8,106  1,156  12,543  13,699  (7,281) 1984 7/2/2001
911 Elkridge Landing Road (O) Linthicum, MD —  1,215  4,861  3,610  1,215  8,471  9,686  (6,123) 1985 4/30/1998
938 Elkridge Landing Road (O) Linthicum, MD —  922  4,748  1,533  922  6,281  7,203  (3,990) 1984 7/2/2001
939 Elkridge Landing Road (O) Linthicum, MD —  939  3,756  8,846  939  12,602  13,541  (6,868) 1983 4/30/1998
9700 Advanced Gateway (O) Huntsville, AL —  —  7,021  —  —  7,021  7,021  —  (7) 3/23/2010
Arundel Preserve (L) Hanover, MD —  13,352  10,799  —  13,352  10,799  24,151  —  (6) 7/2/2007
Canton Crossing Land (L) Baltimore, MD —  —  6,000  54  —  6,054  6,054  (54) (6) 10/27/2009
Canton Crossing Util Distr Ctr (O) Baltimore, MD —  2,866  7,271  2,371  2,866  9,642  12,508  (8,142) 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  8,677  —  705  8,677  9,382  (542) 2022 3/24/2004
M Square Research Park (L) College Park, MD —  —  3,254  —  —  3,254  3,254  —  (6) 1/29/2008
MP 3 (O) Northern Virginia —  9,038  3,134  —  9,038  3,134  12,172  —  (7) 11/8/2018
National Business Park North (L) Annapolis Junction, MD —  15,554  25,740  —  15,554  25,740  41,294  —  (6) 6/29/2006
North Gate Business Park (L) Aberdeen, MD —  1,755  134  —  1,755  134  1,889  —  (6) 9/14/2007
NoVA Office A (O) Chantilly, VA —  2,096  46,849  —  2,096  46,849  48,945  (11,607) 2015 7/18/2002
NoVA Office B (O) Chantilly, VA —  739  38,376  —  739  38,376  39,115  (7,656) 2016 7/18/2002
NoVA Office C (O) Chantilly, VA —  7,751  85,774  —  7,751  85,774  93,525  (6,647) 2021 7/18/2002
NoVA Office D (O) Chantilly, VA —  6,587  40,559  —  6,587  40,559  47,146  (7,516) 2017 7/2/2013
Oak Grove A (O) Northern Virginia —  12,866  42,090  —  12,866  42,090  54,956  (4,333) 2020 11/1/2018
Oak Grove B (O) Northern Virginia —  12,866  41,621  —  12,866  41,621  54,487  (4,951) 2019 11/1/2018
Oak Grove C (O) Northern Virginia —  11,741  79,004  —  11,741  79,004  90,745  (5,300) 2022 11/1/2018
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)
Oak Grove D (O) Northern Virginia —  11,741  78,391  —  11,741  78,391  90,132  (4,041) 2022 11/1/2018
Old Annapolis Road (O) Columbia, MD —  1,637  5,500  6,985  1,637  12,485  14,122  (6,974) 1974/1985 12/14/2000
Patriot Ridge (L) Springfield, VA —  18,517  14,650  —  18,517  14,650  33,167  —  (6) 3/10/2010
Project EL (O) Confidential-USA —  7,190  46,922  —  7,190  46,922  54,112  (4,055) 2021 1/20/2006
Project EX (O) Confidential-USA —  13,010  19,107  —  13,010  19,107  32,117  (2,754) 2018 7/16/2008
PS A (O) Northern Virginia —  4,078  54,767  —  4,078  54,767  58,845  (1,876) 2023 1/27/2005
PS B (O) Northern Virginia —  3,468  47,630  —  3,468  47,630  51,098  (1,238) 2023 1/27/2005
Redstone Gateway (L) Huntsville, AL —  —  36,810  66  —  36,876  36,876  (2) (6) 3/23/2010
Sentry Gateway - T (O) San Antonio, TX —  14,020  38,804  13  14,020  38,817  52,837  (17,354) 1982/2008 3/30/2005
Sentry Gateway - V (O) San Antonio, TX —  —  1,066  —  —  1,066  1,066  (428) 2007 3/30/2005
Sentry Gateway - W (O) San Antonio, TX —  —  1,884  71  —  1,955  1,955  (755) 2009 3/30/2005
Sentry Gateway - X (O) San Antonio, TX —  1,964  21,178  53  1,964  21,231  23,195  (7,526) 2010 1/20/2006
Sentry Gateway - Y (O) San Antonio, TX —  1,964  21,298  73  1,964  21,371  23,335  (7,543) 2010 1/20/2006
Sentry Gateway - Z (O) San Antonio, TX —  1,964  30,573  —  1,964  30,573  32,537  (7,498) 2015 6/14/2005
Southpoint Phase 2 Bldg A (O) Northern Virginia —  4,404  56,542  —  4,404  56,542  60,946  (205) 2024 7/24/2019
Southpoint Phase 2 Bldg B (O) Northern Virginia —  3,752  2,850  —  3,752  2,850  6,602  —  (7) 7/24/2019
Westfields - Park Center (L) Chantilly, VA —  8,667  3,759  —  8,667  3,759  12,426  —  (6) 7/2/2013
Other Developments, including
   intercompany eliminations (V)		 Various —  —  1,140  258  —  1,398  1,398  (200) Various Various
$ 69,756  $ 611,802  $ 3,744,901  $ 811,116  $ 611,802  $ 4,556,017  $ 5,167,819  $ (1,537,293)
(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 $124.6 million, unsecured senior notes of $2.1 billion, unsecured notes payable of $251,000, and deferred financing costs, net of premiums, on the remaining loans of $155,000.
(3)The aggregate cost of these assets for federal income tax purposes was approximately $3.9 billion as of December 31, 2024.
(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, 2024.
(7)Under development as of December 31, 2024.
The following table summarizes our changes in cost of properties for the years ended December 31, 2024, 2023 and 2022 (in thousands):
2024 2023 2022
Beginning balance $ 4,903,840  $ 4,986,537  $ 4,959,709 
Acquisitions of operating properties (1) 24,996  —  — 
Improvements and other additions 239,096  333,081  350,702 
Sales (2) —  (162,981) (323,874)
Impairments (3) —  (252,797) — 
Other dispositions (113) —  — 
Ending balance $ 5,167,819  $ 4,903,840  $ 4,986,537 
The following table summarizes our changes in accumulated depreciation for the same time periods (in thousands):
2024 2023 2022
Beginning balance $ 1,400,162  $ 1,273,448  $ 1,234,908 
Depreciation expense 137,224  132,728  124,803 
Sales (2) —  (6,014) (86,263)
Other dispositions (93) —  — 
Ending balance $ 1,537,293  $ 1,400,162  $ 1,273,448 
(1)Includes acquisitions of two operating properties, as described in Note 4 to our consolidated financial statements. This amount excludes intangible assets associated with acquisitions.
(2)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.
(3)Includes impairment recognized on six operating properties and a parcel of land, as described in Note 4 to our consolidated financial statements.