The Pentagon The Pentagon The Pentagon, in Arlington County, Virginia, across the Potomac River from Washington, D.C., is the headquarters of the United States Department of Defense. As a symbol of the U.S. military, the phrase "The Pentagon" is often used as a metonym for the Department of Defense and its leadership. The building was designed by American architect George Bergstrom and built by contractor John McShain. Ground was broken on September 11, 1941, and the building was dedicated on January 15, 1943. General Brehon Somervell provided the major motivating power behind the project; Colonel Leslie Groves was responsible for overseeing the
Arlington County, Virginia in the county, while 86% commute in, with 27% commuting from Fairfax County. An additional 92,784 people commute out for work, with 42% commuting to DC, and 29% commuting to Fairfax County. A number of federal agencies are headquartered in Arlington, including the Air Force Office of Scientific Research, American Battle Monuments Commission, DARPA, Diplomatic Security Service, Drug Enforcement Administration, Foreign Service Institute, the DHS National Protection and Programs Directorate, Office of Naval Research, Transportation Security Administration, United States Department of Defense, United States Marshals Service, and the United States Trade and Development Agency. Companies headquartered in Arlington include AES,