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 Fire Department and provide emergency and support services to Arlington County. Prior to 1950, independent volunteer fire companies protected Arlington County. As the demand for services for fire and EMS grew, the need for full-time paid staff was acknowledged by the County. Staff was hired, first to augment the volunteers, then finally to provide the full range of services required in a modern, urban, fire department. The volunteer members ride as supplemental staffing on apparatus and do not count as minimum staffing. The Arlington County Fire Department uses the volunteer apparatus for providing support services, such as special event stand-bys, storm and