Fort Huachuca is a United States Army installation under the command of the United States Army Installation Management Command. It is located in Cochise County, in southeast Arizona, about 15 miles north of the border with Mexico. Beginning in 1913, for 20 years the fort was the base for the Buffalo Soldiers, the 10th Cavalry Regiment. During the buildup of World War II, the fort had quarters for more than 25,000 men.Fort Huachuca is also the headquarters of Army Military Auxiliary Radio System. Other tenant agencies include the Joint Interoperability Test Command, Information Systems Engineering Command (ISEC) and the Electronic Proving Ground.The fort is also the home to the Western Division of the Advanced Airlift Tactics Training Center (AATTC) which is based at the 139th Airlift Wing, Rosecrans Air National Guard Base, Saint Joseph, Missouri.