Fort Sumner is a U.S. village in De Baca County, New Mexico. The population was 1,031 at the 2010 U.S. Census, down from 1,249 at the 2000 U.S. Census. It is the county seat of De Baca County. Fort Sumner is the spring and fall home of the Columbia Scientific Balloon Facility, and is home to the burial site of famed outlaw of the American West, Billy the Kid, who was shot and killed here in 1881.