High Quality Content by WIKIPEDIA articles! The Salt River (O'odham: Onk Akimel) is a stream in the U.S. state of Arizona. It is the largest tributary of the Gila River. The river is about 200 miles (320 km) long. Its drainage basin is about 13,700 square miles (35,000 km2) large. The longest of the Salt River's many tributaries is the 195-mile (314 km) Verde River. The Salt's headwaters tributaries, the Black River and East Fork, increase the river's total length to about 300 miles (480 km).