Sentinel Peak is a 2,897 ft (900 m) peak in the Tucson Mountains southwest of downtown Tucson, Arizona, United States. The valley's first inhabitants grew crops at the mountain's base, along the Santa Cruz River. The name "Tucson" is derived from the O'odham Cuk Ṣon, meaning "[at the] base of the black [hill]". In the 1910s, University of Arizona students used local basalt rock to construct a 160 ft (50 m) tall block "A" on the mountain's east face, near its summit, giving the peak its other name, "A" Mountain. The peak is part of a 272-acre park, the largest natural resource park in the City of Tucson.

Tempe Butte is the official name of an andesite butte of volcanic origin, located partially on Arizona State University's Tempe campus in Tempe, Arizona. It is often referred to by locals as A Mountain, after the 60-foot-tall (18 m) gold-painted letter 'A' near the top. Another name for the area, used by the City of Tempe, is Hayden Butte.