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 Armed Forces. The DOD is the largest employer in the world, with over 1.4 million active-duty service members (soldiers, Marines, sailors, airmen, and Guardians) as of 2021. More employees include over 826,000 National Guard and reservists from the armed forces, and over 732,000 civilians bringing the total to over 2.8 million employees. 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 secu