Gila

Gila, river of the southwestern United States, rising in the mountains of southwestern New Mexico and flowing westward across Arizona to join the Colorado River, near Yuma. For the greater part of its total course, which is 1,044 km (649 mi), the Gila flows through mountain canyons. The lower part of its course is through open and comparatively level country, where the climate of the river valley is semitropical and the land is made fertile by irrigation from the river. Coolidge Dam, on the Gila in eastern Arizona, impounds water for the irrigation of the Casa Grande Valley around Florence and Casa Grande. Numerous remains of prehistoric Native American dwellings, among which are those contained in the Gila Cliff Dwellings and Casa Grande Ruins national monuments, are situated along the banks of the river or of its tributaries. In addition, the river passes through the San Carlos, Gila River, and Gila Bend Indian reservations.