Vast central lowland of California, USA, 80–130 km/50–80 mi wide, running some 720 km/450 mi north-northwest to south-southeast, between the Sierra Nevada and the Cascade Range (to the east) and the Coast Ranges (to the west). Its two sections are also known, after their major rivers, as the Sacramento Valley (to the north) and San Joaquin Valley (to the south). The valley is a sediment-filled, flat plain, and was formerly a coastal swamp; the ranges on either side are newer products of California's ongoing mountain building processes. In its centre, the Sacramento and San Joaquin rivers meet in a complex delta, draining west through San Francisco Bay. The potential of the arid southern San Joaquin Valley led to the establishment (1935) of the Central Valley Project, which has created dozens of dams, reservoirs, and canals from Shasta Lake (in the north) to the Bakersfield area and the Tehachapi Mountains, at the valley's southern end. As a result, the San Joaquin Valley has become the heartland of California agriculture and a major supplier of fruits, nuts, grapes, vegetables, and other produce. More recently, the California Aqueduct and other units of the California State Water Project have brought water through the valley to Southern California's cities. Ranching is important in places, and there are important oilfields in the far south, near Bakersfield. The valley's major cities are (from south to north) Bakersfield, Fresno, Stockton, and Sacramento.
In the Spanish period, the valley was little used except for cattle ranchos. With the discovery of gold on the American River in 1848, however, the Sacramento Valley filled rapidly with fortune seekers. After the gold rush died down, agriculture established itself along the rivers.