



Sentinel Peak is a 2,897 ft (883 m) peak in the Tucson Mountains southwest of downtown Tucson, Arizona. 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 [tʃʊk ʂɔːn], meaning "[at the] base of the black [hill]". In the 1910s, University of Arizona students used local basalt rock to construct a 160-ft-tall (49 m) 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 (110 hectares) park, the largest natural resource park in the City of Tucson. == Early history == The fertile land at the base of Sentinel Peak was used for agriculture from circa 2000 BCE until the 1930s. Bedrock mortars found on the sides of the peak are believed to have been used to grind corn and mesquite beans into flour. In the 1690s, the O'odham people living in the area were visited by Father Eusebio Francisco Kino, who established the nearby Mission San Xavier del Bac. After Presidio San Augustin del Tucson was constructed in 1775, sentinels were stationed on the peak to watch for raiding Apaches. == Geology == Sentinel Peak is made up of several layers of igneous rock representing various types of volcanic activity, though the mountain itself is not a volcano. SOURCESWikipedia