San Joaquin River, << `san` waw KEEN, >> is the chief stream in the southern part of the Central Valley of California. It rises on the western slope of the Sierra Nevada in Fresno County. The river flows southwest out of the Sierra Nevada and crosses the San Joaquin Valley, one of the richest farming areas in the United States. It then turns northwest and joins the Sacramento River to form a delta. Water from the delta empties into San Francisco Bay.
The San Joaquin River is about 350 miles (563 kilometers) long. Its waters are used in the Central Valley Project, which distributes water for irrigation and for the generation of hydroelectric power. Friant Dam, part of the project, stands on the river.