The Skeleton Canyon massacres refer to two separate attacks on Mexican citizens in 1879 and 1881. Skeleton Canyon is located in the Peloncillo Mountains (Hidalgo County), which straddles the modern Arizona and New Mexico state line border. This canyon connects the Animas Valley of New Mexico with the San Simon Valley of Arizona.
The first Skeleton Canyon Massacre occurred in 1879 when a group of Mexican Rurales were ambushed by cattle rustlers. In July 1879, several rustlers attacked a rancho in northern Sonora, killing several of the inhabitants. After the attack on the rancho, the survivors reported the attacks to Commandant Francisco Neri, who sent out a detachment of Rurales, including Captain Alfredo Carrillo. The Rurales illegally crossed the border into Arizona. As they entered Skeleton Canyon, shots were fired against them. Three of the Rurales survived the initial onslaught. The posse leader was killed by execution.
No action was taken by the Mexican Government, but it protested the killings to President Chester Arthur, although acknowledging the Mexican policemen had crossed illegally into the United States, where they had no jurisdiction. Johnny Ringo, considered to be one of an outlaw group known as the Cowboys, who were cattle rustlers and bandits, claimed to have been at the ambush. He said others there, who participated in the murders, were Old Man Clanton, brothers Ike and Billy Clanton, "Curly Bill" Brocius, Florentino Cruz, brothers Frank and Tom McLaury, Jim Hughes, Rattlesnake Bill; Joe Hill; Charlie Snow; Jake Guage; and Charlie Thomas.
In July 1881, "Curly Bill" Brocius learned that several Mexican smugglers carrying silver were heading to the United States through Skeleton Canyon.Curly Bill and several other men including Johnny Ringo, Newman Haynes Clanton, Ike Clanton, Billy Clanton, Frank McLaury, Tom McLaury, Billy Grounds, and Zwing Hunt hid in the rocks high above the trail. As the smugglers rode through the canyon, the Cowboys opened fire, killing six of the fifteen. The Americans followed up, killing the remaining eleven smugglers before they could escape. Some reports said the men were tortured before being killed.