The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on a 2,096 m (6,880 ft) peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, 88 kilometers (55 miles) southwest of Tucson. The observatory is considered to be part of the National Optical Astronomy Observatory (NOAO), although some of the telescopes located here, like those at the MDM Observatory, belong to other groups such as the University of Arizona's Steward Observatory. With 23 telescopes, it is the largest, most diverse gathering of astronomical instruments in the world.