Valley, California, U.S. Located between the Sierra Nevada and the Coast Ranges , it is more than 400 mi (640 km) long and 2050 mi (3280 km) wide.
The Sacramento and San Joaquin rivers, which run through the valley, are fed by abundant rains and melting snows of the Sierras. Because of the irrigation made possible by numerous dams and canals, the area now contains some of the richest farmland in the U.S.