Tucson was founded as a military fort by the Spanish when Hugo O’Conor authorized the construction of Presidio San Agustín del Tucsón in 1775. It was included in the state of Sonora after Mexico gained independence from the Spanish Empire in 1821. In 1853, the United States acquired a 29,670 square miles region of present-day southern Arizona and southwestern New Mexico from Mexico under the Gadsden Purchase. Tucson served as the capital of the Arizona Territory from 1867 to 1877. Tucson was Arizona’s largest city by population during the territorial period and early statehood until it was surpassed by Phoenix by 1920. Nevertheless, population growth remained strong during the late 20th century. In 2017, Tucson was the first American city to be designated a “City of Gastronomy” by UNESCO.

The Spanish name of the city, Tucsón [tukˈson], is derived from the O’odham Cuk Ṣon, meaning “(at the) base of the black [hill]”, a reference to a basalt-covered hill now known as Sentinel Peak. Tucson is sometimes referred to as “The Old Pueblo”.