Tumamoc Hill (O'odham: Cemamagĭ Doʼag) is a butte located immediately west of "A" Mountain and downtown Tucson, Arizona. It is home to many radio, television, and public safety transmitters. The University of Arizona (UA) owns a 340-acre (1.4 km²) preserve and leases another 509 acres (2.06 km²) as a research and education facility. The Steward Observatory maintains a small astronomical observatory with a 20-inch (510 mm) telescope on the hill.