San Pedro River (Arizona)

San Pedro River (Arizona)

San Pedro River is a northward-flowing stream originating about 10 miles (16 km) south of Sierra Vista, Arizona, near Cananea, Sonora, Mexico. It is one of only two rivers which flow north from Mexico into the United States. The river flows 140 miles (230 km) north through Cochise County, Pima County, Graham County, and Pinal County to its confluence with the Gila River, at Winkelman, Arizona. It is the last major, free-flowing undammed river in the American Southwest, it is of major ecological importance as it hosts two-thirds of the avian diversity in the United States, including 100 species of breeding birds and 300 species of migrating birds.