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 House, The Robert E. Lee Memorial of Alexandria County to Arlington County to end ongoing confusion between Alexandria County and the independent city of Alexandria. The name Arlington was chosen to reflect the presence of the Arlington estate. On March 4, 1925, the 68th United States Congress enacted Public Resolution 74, which authorized the restoration of the Lee Mansion in the Arlington National Cemetery, Virginia. The War Department then began to restore Arlington House, and the Department of the Army continues to manage over half of the original plantation's 1,100 acres, as Arlington National Cemetery. However, for several years after Congress enacted the authorizing legislation, the