Claim: There is a desert in California.

The Central Valley is a large , flat valley that dominates the geographical center of the U.S. state of California . It is 40 to wide and stretches approximately 450 mi from north-northwest to south-southeast , inland from and parallel to the Pacific Ocean coast . It covers approximately 18000 mi2 , about 11 % of California 's total land area -LRB- or about the size of Denmark -RRB- . Bounded by the Sierra Nevada to the east and the Coast Ranges to the west , it is California 's single most productive agricultural region and one of the most productive in the world , providing more than half of the fruits , vegetables and nuts grown in the United States . More than 7 million acres -LRB- 28,000 km2 -RRB- of the valley are irrigated via an extensive system of reservoirs and canals . The valley also has many major cities , including the state capital Sacramento ; as well as Redding , Stockton , Modesto , Fresno and Bakersfield .   The Central Valley watershed comprises 60000 mi2 , or over a third of California . Its three main drainage systems are the Sacramento Valley in the north , which receives well over 20 in of rain annually ; the drier San Joaquin Valley in the south , and the Tulare Basin and its semi-arid desert climate at the southernmost end . The Sacramento and San Joaquin river systems drain their respective valleys and meet to form the Sacramento-San Joaquin River Delta , a large expanse of interconnected canals , stream beds , sloughs , marshes and peat islands . The delta empties into the San Francisco Bay , and then ultimately flows into the Pacific . The waters of the Tulare Basin essentially never flow to the ocean -LRB- with the exception of Kings River waters diverted northward for irrigation -RRB- , though they are connected by man-made canals to the San Joaquin and could drain there again naturally if they were ever to rise high enough .   The valley encompasses all or parts of 18 Northern California counties : Butte , Colusa , Glenn , El Dorado , Fresno , Kings , Madera , Merced , Placer , San Joaquin , Sacramento , Shasta , Stanislaus , Sutter , Tehama , Tulare , Yuba , Yolo , and the Southern California county of Kern .