Fort Buchanan was a United States army base in Arizona, to control land purchased in the Gadsden Purchase.

Today there is a United States army base in Guaynabo, Puerto Rico of the same name. It was established in 1923, and in 1999 became the headquarters for USARSO. Major General Alfred Valenzuela commanded USARSO but in 2003 USARSO headquarters was moved to Fort Sam Houston in Austin, Texas. Today the fort services the 65 Reserve and Puerto Rico National Guard.

The base contains: 4 schools Antilles Elementary School, Antilles Intermidiate School, Antilles Middle School, Antilles High School; one golf course Fort Buchanan Golf Course; a PX main store; a class six shoppette; a bowling alley; a fitness center; a outdoor pool facility; a chapel; a library; a Banco Popular; a community club among other things.