United States Department of Defense
The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national security and the United States Military. Headquartered at the Pentagon in Arlington, Virginia, just outside Washington, D.C., the DoD's stated mission is to provide "the military forces needed to deter war and ensure our nation's security".
The Department of Defense is headed by the secretary of defense, a cabinet-level head who reports directly to the president of the United States. Beneath the Department of Defense are three subordinate military departments: the Department of the Army, the Department of the Navy, and the Department of the Air Force. In addition, two national intelligence services are subordinate to the Department of Defense: the Defense Intelligence Agency (DIA) and the National Security Agency (NSA). The Department of Defense also oversees the Defense Force Protection Agency (DFPA), the Department of Defense Office of the Inspector General (OIG), and the Defense Criminal Investigative Service (DCIS) . Military operations are managed by the Chairman of the Joint Chiefs of Staff.