An Apache reservation in Arizona located in the Coconino National Forest. It was the home to the X-Man Thunderbird and his younger brother Warpath. Eventually both men left the reservation and went to New York in hopes of learning how to cope with their mutant powers.
When the young Warpath went back to his home years later, he saw it was destroyed, apparently by the Hellfire Club, seeing how there where masks of it's shock-troops on the ground. It was later revealed to have been destroyed by Stryfe and the Mutant Liberation Front. Some months later, it served as a one-time home to the renegade X-Force team.
Trivia: Camp Verde exists in the real world as well, located in Arizona.