The Guadalupe Canyon Massacre was an incident that occurred on August 13, 1881 in the Guadalupe Canyon area of the southern Peloncillo Mountains – Guadalupe Mountains. Five American men were killed in an ambush, including "Old Man" Clanton, the alleged leader. They were believed to belong to The Cowboys, an outlaw group based in Pima and Cochise counties in Arizona. Two men survived the attack. The canyon straddles the modern Arizona and New Mexico state line and connects the Animas Valley of New Mexico with the San Bernardino Valley of Arizona. During the American Old West, the canyon was a key route for smugglers into and out of Mexico.