The first Spanish settlers arrived in the late 17th cent., and in 1700, Father Eusebio Kino founded Mission San Xavier del Bac 9 mi (14.5 km) south of the Native American village of Tucson. The city was established (1776) as a walled presidio. Tucson became a military border post of New Spain, of Mexico, and, after its transfer under the Gadsden Purchase, of the United States. It served as territorial capital from 1867 to 1877. In 1873, Fort Lowell was built 2 mi (3.2 km) north of the city. The Southern Pacific RR (see Southern Pacific Company) arrived in 1880.

Among the city's many points of interest are the "Old Adobe" (1868); Colossal Cave; Fort Lowell (reconstructed, now a museum); the beautiful nearby San Xavier mission (present building erected 1783-97); and Tucson Mountain Park—with "Old Tucson Studios," a movie-set replica, and the Arizona-Sonora Desert Museum—and Saguaro National Park to the west. Tucson has a symphony orchestra as well as opera and ballet companies. Museums include the Tucson Museum of Art, the Univ. of Arizona Museum of Art, and the Arizona Historical Society Museum. A fiesta and rodeo is held each February, and several major-league baseball teams have spring training camps in the area. Tucson is the seat of the Univ. of Arizona. Nearby military installations are the large Davis-Monthan Air Force Base and U.S. Fort Huachuca, an army electronics proving ground, with strategic communications headquarters and an intelligence school.