Approximately 4,000 U.S. Marshals and Deputy U.S. Marshals form the backbone of the United States Marshals Service, an agency that has served the United States since 1789. The U.S. Marshals Service serves as the enforcement arm of the federal courts and is involved in virtually every federal law enforcement initiative. The Marshals' duties include protecting the federal judiciary, apprehending federal fugitives, housing and transporting federal prisoners, managing and selling seized assets acquired by criminals through illegal activities, and operating the Witness Security Program. The Marshals perform all these roles by coordinating efforts with other federal, state and local law enforcement agencies. This cooperation has been a cornerstone of the Marshals Service since its inception. The agency's headquarters is located in Arlington, VA, and provides support to 94 district offices across the country, including the District of Columbia, the Commonwealth of Puerto Rico and three territories of the United States -- the Virgin Islands, Guam and the Northern Mariana Islands.