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 Arlington County, Virginia Arlington County is a county in the Commonwealth of Virginia, often referred to simply as Arlington or Arlington, Virginia. In 2016, the county's population was estimated at 230,050, making it the sixth-largest county in Virginia, or the fourth-largest city if it were incorporated as such. It is the 5th highest-income county in the U.S. by median family income, and has the highest concentration of singles in the region. The county is coterminous with the U.S. Census Bureau's census-designated place of Arlington. Though a county, it is also treated as the second-largest principal city of the Washington metropolitan