SONORA

estado (state), northwestern Mexico, bounded on the north by the United States, on the east by Chihuahua, on the south by Sinaloa, and on the west by Baja California and the Gulf of California. The name (meaning sonorous) is from local deposits of marble, which when struck emit a bell-like sound. Explored by Spaniards in the 1530s, Sonora became an important colonial copper-, gold-, and silver-mining district. Generally arid and semiarid climatic conditions necessitate irrigation, with which winter vegetables, cereals, cotton, tobacco, and corn (maize) can be cultivated. Sonora became a state in 1830, but the Yaqui Indian tribes were not finally subdued until the 20th century. The population is clustered around Heroica Nogales, at the Arizona border; Hermosillo, the state capital; Guaymas, a gulf port and deep-sea fishing resort; and Ciudad Obregn, in the Yaqui valley. Since the 1940s, these and other communities have flourished, their cotton-growing hinterlands developed by irrigation projects. Major highways and railroads from Mexicali and Heroica Nogales to Mexico City traverse the state. Airports are situated in the major cities. Area 70,291 square miles (182,052 square km). Pop. (1990) 1,823,606.