There is a desert in California.
California . California 's diverse geography ranges from the Pacific Coast in the west to the Sierra Nevada mountain range in the east ; and from the redwood -- Douglas fir forests in the northwest to the Mojave Desert in the southeast . The Central Valley , a major agricultural area , dominates the state 's center . The Central Valley is a large , flat valley that dominates the geographical center of the U.S. state 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 . San Bernardino County , officially the County of San Bernardino , is a county located in the southern portion of the U.S. state of California .