The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory site located on 2,096 m (6,880 ft) Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, 88 kilometers (55 mi) west-southwest of Tucson, Arizona. With 24 optical and two radio telescopes, it is the largest, most diverse gathering of astronomical instruments in the world.