Humphreys Peak, about 11 miles north of Flagstaff in the Kachina Peaks Wilderness, is Arizona’s highest mountain at 12,637 feet and the loftiest summit of the dormant volcanic San Francisco Peaks. Known in Hopi as Aaloosaktukwi and in Navajo as Dookʼoʼoosłííd, it was reshaped by volcanic collapse and later by Pleistocene glaciers. Its upper slopes rise above treeline into steep, rocky terrain with a severe subarctic climate, making lightning and sudden weather serious hazards. Long popular for hiking and skiing, the mountain was named around 1870 for Union general Andrew A. Humphreys, with its official naming corrected in 1933.