Canyon e Chelly National Monument, established April 1, 1931 as a unit of the National Park Service, is located in northeastern Arizona, within the boundaries of the Navajo Nation. The monument covers 131 square miles (339 km²) and encompasses the floors and rims of the three major canyons: de Chelly, del Muerto, and Monument. These canyons were cut by streams with headwaters in the Chuska mountains just to the east of the monument.