In November 1941 , the United States Marine Corps moved their headquarters from the Main Navy Building on the National Mall to the Navy Annex , where it would stay until 1996 . During this time the Commandant of the Marine Corps was the only one of the four Department of Defense service chiefs who did not have his office in the Pentagon . The Missile Defense Agency also came to be located in the Navy Annex . During the September 11 attacks , when the Navy Command Center at the Pentagon was destroyed , it was reconstituted at the Navy Annex
September 11 attacks
September 11 attacks
Navy Annex