TUCSON (too-son'), a city in southeastern Arizona, lying in the broad valley of the Santa Cruz river. It is about 2,400 ft. above sea level and is sheltered by mountains 5,000-9,000 ft. high. Pop. (1910) 13,193; (1920) 20,292 ; in 1930 by the Federal census 32,506. In 1920 5,181 were foreign-born, of which 82% were Mexicans. Tucson has many irrigated farms in its vicinity and is the centre of one of the oldest agricultural districts of the State. Its climate is dry, mild and equable and attracts many winter visitors. It is on the main line of the Southern Pacific railway and is also the northern terminus of the Southern Pacific of Mexico railway, which gives direct service to Guadalajara and Mexico City. The Southern Pacific has its division headquarters and repair shops in the city.
The University of Arizona (1891; non-sectarian, coeducational) occupies a campus of 75 ac. upon a high hill in the northeastern part of the city. Its attendance increased from 201 in 1909 to 1,778 in the winter session 1926-27. There are 22 buildings, II of them built since 1910. Among them are the University library, containing 70,000 volumes, and Steward Observatory. Connected with the university is the State Museum, which houses extensive archaeological and natural history collections. At Tucson are also the Southwest experiment station of the U. S. Bureau of Mines and a desert botanical laboratory maintained by the Carnegie In stitution of Washington. In 1900 Tucson became the see of a Roman Catholic bishop and the church maintains a cathedral, St. Joseph's Academy and San Xavier Mission for Indians. The city has an excellent Carnegie library.
In the immediate vicinity lie ruined villages of the ancient Pueblo peoples. In history Tucson is first heard of in 1699 as an Indian rancheria or settlement. In 1763 it was a visits of the Jesuit mission of San Xavier del Bac, founded between 1720 and 1732, 9 m. south of Tucson. It was made a presidio (San Augus tin del Tugison), or military outpost in 1776, and, although a few Spaniards may have lived there before, the founding of Tucson as a Spanish town dates from this time. It was never afterward abandoned during the Indian Wars. The first decade of the 19th century was the apex of its prosperity under Spanish rule, and its population was between 2,000 and 3,00o people. By 1848 this number had dwindled to 76o. Tucson lay within the territory acquired by the United States by the Gadsen Purchase in 1853. It was occupied by the United States in 1856, and with the arrival of American troops and traders a new era of prosperity began. In the 6o's and 70's the place witnessed considerable commercial activity, it being a general pack-train centre. In 186o the Weekly Arizonian, the first newspaper in the State, was established there. Fort Lowell, 7 m. north-east of the city, was built in 1873 as a protection against the Apache Indians; it was abandoned in 1891. Tucson was occupied by the Confederates in Feb. 1862, and by the Union forces in May. It was the territorial capital from 1867 to 1877. The Southern Pacific railway arrived from the West in 1880, and in 1910 the connection with the Mexican railways was made. Tucson was chartered as a city in 1883.