SONORA RIVER

river in Sonora state, northwestern Mexico. It rises south of Cananea, near the U.S. border, and flows southward and then southwestward through the western flanks of the Sierra Madre Occidental. Below Hermosillo, the state capital, the river crosses the coastal lowlands and empties into the Gulf of California opposite Tiburn Island. Its total course is some 250 miles (400 km) long. Many settlements, including Arizpe, Moctezuma, Ures, and Hermosillo, lie along the river, and, although it reaches the gulf only in years of heavy rainfall, it is used for irrigation, especially near Hermosillo.