Río Sonora (Sonora River) is a 402-kilometer-long river of Mexico. It lies on the Pacific slope of the Mexican state of Sonora and it runs into the Gulf of California.

Watershed

The Sonora River watershed covers 10,040 sqmi of public land. Slopes range from steep orientations in the upper part of the watershed to more gradual topographies in the valleys. The Sonora River watershed is subdivided into six smaller watersheds.

Ecology

Biotic communities found within the watershed in order of importance by the area covered are the Sinaloan thornscrub, the plains of Sonora subdivision, semidesert grasslands, the Madrean evergreen woodland, and the central gulf coast subdivision. Average annual precipitation is 375 mm which occurs in two seasons, late summer-early fall and winter-early spring. Physician naturalist Edgar Alexander Mearns' 1907 report of beaver (Castor canadensis) on the Sonora River may be the southernmost extent of the range of this North American aquatic mammal.