General Dynamics Headquarters, Virginia

General Dynamics is one of the largest defense contractors in the USA, and is best known for its ship building. It owns Electric Boat, which has been the primary builder of military submarines for more than a century, based mostly out of Groton, Connecticut. General Dynamics also owns major military shipyards in Maine, Norfolk, Mayport, and San Diego. It made military aircraft and missiles after buying Convair in 1953. It also makes land based military vehicles, including tanks and armored vehicles. Its Mission Systems division works in information technology and security, which originated with its acquisition of GTE’s Government Systems in 1999.