United States Department of Defense United States Department of Defense The 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 concerned directly with national security and the United States Armed Forces. The department is the largest employer in the world, with nearly 1.3 million active duty servicemen and women as of 2016. Adding to its employees are over 826,000 National Guardsmen and Reservists from the four services, and over 742,000 civilians bringing the total to over 2.8 million employees. Headquartered at the Pentagon in Arlington, Virginia,
Arlington County, Virginia the vast majority originating from Washington Metro stations. Arlington is served by the Orange, Blue, Yellow, and Silver lines of the Washington Metro. The Metro stations in Arlington are the only stations outside of Washington, D.C. where the system's original Brutalist architecture can be found. Additionally, Arlington is served by Virginia Railway Express commuter rail, Metrobus (regional public bus), Fairfax Connector (regional public bus), Potomac and Rappahannock Transportation Commission (PRTC) (regional public bus), (DASH bus) (regional public bus) and a county public bus system, Arlington Transit (ART). Metroway, the first bus rapid transit (BRT) in the D.C. area, is a