The Peloncillo Mountains of Hidalgo County, (Spanish language pelo, hair, pelón, hairless, bald; peloncillo, Little Baldy), is a major 35-mile (56 km) long mountain range southwest of New Mexico's Hidalgo County, and also part of the New Mexico Bootheel region.

The Peloncillo Mountains lie in a region of southeast Arizona, southwest New Mexico, northeast Sonora, and extreme northwest Chihuahua called the Madrean Sky Islands.

The Peloncillo Mountains are mostly north-south trending, but curving northeasterly at the north end.

Historical battles, and Indian Wars caused retreat into this mountain region; it was also access and escape routes into the safe haven ranges of northern Mexico.

The region is famous for Skeleton Canyon and the historical events, including the surrender of Geronimo, that occurred there.