California Geographic Overview

Central Valley and the Bay Area

The center of the state is an elongated plain, the Central Valley. The fertile soil and favorable climate make the valley a rich and varied agricultural area, where 230 different agricultural products are grown (one third of the total number in the US). There are also a number of major population centers such as Sacramento (the state capital), Modesto and Fresno. The Central Valley is drained by the San Joaquin (southern half) and the Sacramento (northern half). The rivers together form a large inverted delta, the Sacramento-San Joaquin Delta, which divides the Central Valley in two and supplies drinking water to more than 23 million people (two-thirds of the state’s population) through an irrigation system. The delta opens into a large estuary, most of which is called San Francisco Bay, while a portion in the northeast is called San Pablo Bay. The river delta is connected to San Pablo Bay by Suisun Bay and the Strait of Carquinez.

According to, the area around the San Francisco Bay consists of a large urban agglomeration. Called the Bay Area, it includes the cities of San Francisco, San Jose, Oakland, and Berkeley. The southern part of the Bay Area, near San Jose, is nicknamed Silicon Valley. There is a concentration of computer industry in this area. The San Francisco Bay is in contact with the ocean through a close connection. This connection, north of San Francisco, is called the Golden Gate.

North and East

To the east, the Central Valley is bordered by a high mountain range, the Sierra Nevada (Spanish for snowy mountain range). This mountain range takes its name from the perpetual snow on the highest slopes and forms a barrier between the fertile lowlands and coastal regions of California and the rest of the United States. Some of the highest peaks are Mount Whitney (4,421 m, the highest point in the US outside Alaska), Mount Darwin (4,218 m) and Mount Ritter (4,010 m). There are a number of lakes in the Sierra Nevada, of which Lake Tahoe (partly in Nevada) and Mono Lake are the largest.

The Central Valley is separated from the ocean by the Pacific Coast Ranges and bounded on the south by the Tehachapi Mountains. Both chains are nowhere higher than 2500 meters. North and northeast of the Central Valley are the Cascades, a mountain range that is actually the continuation of the Sierra Nevada but was geologically recently volcanically active. The highest peaks, such as Lassen Peak (3192 m) and Mount Shasta (4317 m), are dormant volcanoes. Along the coast, the Coast Ranges merge north into the Klamath Mountains on the Oregon border.

View of downtown Los Angeles with the San Gabriel Mountains in the background

East of the Sierra Nevada and the Cascades begins the Basin and Range Province, a vast area physiographically distinguished by a basin and range topography, an alternation of elongated mountain ranges and flat valleys. East of the Cascades is the Modoc Plateau, which lies partly in Oregon and Nevada. The first valley east of the Sierra Nevada is Owens Valley. This valley separates the Sierra Nevada from the White Mountains, with the highest point being White Mountain Peak (4,344 m). The Owens River flows through the valley, flowing into Owens Lake until the early 1900s., but both the river and lake are now dry as a result of tapping water for the irrigation and water supply of the city of Los Angeles.


In southern California, the coast recedes into a coastal plain, home to Los Angeles, the state’s largest city. Los Angeles is the center of a large metropolitan agglomeration (the Greater Los Angeles Area), which is home to a total of between 13 and 18 million people. The inland urbanized area surrounding the cities of San Bernardino and Riverside in the San Bernardino Valley is considered a separate metropolitan agglomeration, referred to as Inland Empire.

Off the coast are the eight Channel Islands, five of which are protected in the Channel Islands National Park. Inland from Los Angeles are the Transverse Ranges with the highest point being San Gorgonio Mountain (3501 m) in the San Bernardino Mountains. The interior here has no high mountain ranges, but consists of a basin-and-range topography. Much of this interior is desert, including Death Valley, the Colorado Desert (part of the Sonoran Desert that runs through Mexico), and the Mojave Desert.. In Death Valley is the lowest point in North America (at Badwater, 86 meters below sea level).

Even further south is the Salton Sea, a large endorheic salt lake. To the east, the border with Arizona is formed by the Colorado River. In the far south on the coast is California’s second largest city, San Diego.

California Geographic Overview

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