Organizational structure of the United States Department of Defense of the Treasury. According to the U.S. Code, the Coast Guard is at all times considered one of the five armed services of the United States. During times of declared war (or by Congressional direction), the Coast Guard operates as a part of the Navy; this has not happened since World War II, but members have served in undeclared wars and conflicts since then while the service remained in its peacetime department. The Pentagon, in Arlington County, Virginia, across the Potomac River from Washington, D.C., is the Department's headquarters. The Department is protected by the Pentagon Force Protection Agency, which
Arlington County, Virginia property. (Ultimately, the name is a variant of Harlington, London, seat of the first Baron of Arlington; it in turn derives from Hygerǣd, an Anglo-Saxon noble's name.) George Washington Parke Custis, grandson of First Lady Martha Washington, acquired this land in 1802. The estate was eventually passed down to Mary Anna Custis Lee, wife of General Robert E. Lee. The property later became Arlington National Cemetery during the American Civil War, and eventually lent its name to present-day Arlington County. The area that now contains Arlington County was ceded to the new United States federal government by Virginia. With the