Marine Barracks Washington, also known as "8th & I," is the oldest active post in the Marine Corps. Located on the corners of 8th & I streets in southeast Washington, D.C., the Barracks supports both ceremonial and security missions in the nation's capital.

The selection of the location of Marine Barracks Washington was of national and strategic interest. President Thomas Jefferson accompanied by the second commandant of the Marine Corps, Lieutenant Colonel William Ward Burrows, searched for a suitable location to station the Marines within proximity to the Washington Navy Yard and within "an easy marching distance of the Capitol."