Fort Buchanan is the only United States Army installation located on the island of Puerto Rico inside the capital city of San Juan. After passing hands between the Army and Navy a number of times, Fort Buchanan now consists of 746 acres and serves approximately 13,000 people including military personnel and their families as well as retirees and DoD civilians. It is used primarily for Reserve and National Guard units for forward operations in the Caribbean area.

Originally created by the Japanese as an Imperial Army Academy in the 1930’s, it came under American control when a battalion of the 1st Cavalry Division of the U.S. Army arrived on Sept. 5, 1945. It eventually became known as Camp Zama. It saw increased activity during the Vietnam War, as soldiers were sent there for additional medical care of R&R and it was used as a main supply center for the war effort. Changes were made as Japan regained more control of various towns. U.S. Army Garrison Japan was activated at Camp Zama on Oct. 15, 2002.