Chiricahua Peak, the 9,773-foot highest summit in the Chiricahua Mountains and the highest point in Cochise County, rises in southeastern Arizona about 35 miles north of the United States–Mexico border. Formed by a violent volcanic eruption about 27 million years ago, it supports one of the world’s southernmost stands of Engelmann spruce, while its north slope also holds extensive quaking aspen. Recent fires have badly burned much of the peak, and aspens have spread into areas once occupied by evergreen forest. In 2011, the Horseshoe 2 Fire burned 223,000 acres in the Chiricahua Mountains, damaging the trail system, which still sees only limited volunteer maintenance.