California is the 3rd largest state in the United States in area, after Alaska and Texas. California is often geographically bisected into two regions, Southern California, comprising the 10 southernmost counties, and Northern California, comprising the 48 northernmost counties. It is bordered by Oregon to the north, Nevada to the east and northeast, Arizona to the southeast, the Pacific Ocean to the west and it shares an international border with the Mexican state of Baja California to the south (with which it makes up part of The Californias region of North America, alongside Baja California Sur).
In the middle of the state lies the California Central Valley, bounded by the Sierra Nevada in the east, the coastal mountain ranges in the west, the Cascade Range to the north and by the Tehachapi Mountains in the south. The Central Valley is California’s productive agricultural heartland.
Divided in two by the Sacramento-San Joaquin River Delta, the northern portion, the Sacramento Valley serves as the watershed of the Sacramento River, while the southern portion, the San Joaquin Valley is the watershed for the San Joaquin River.
Both valleys derive their names from the rivers that flow through them. With dredging, the Sacramento and the San Joaquin Rivers have remained deep enough for several inland cities to be seaports.
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The Sacramento-San Joaquin River Delta is a critical water supply hub for the state. Water is diverted from the delta and through an extensive network of pumps and canals that traverse nearly the length of the state, to the Central Valley and the State Water Projects and other needs. Water from the Delta provides drinking water for nearly 23 million people, almost two-thirds of the state’s population as well as water for farmers on the west side of the San Joaquin Valley.
Suisun Bay lies at the confluence of the Sacramento and San Joaquin Rivers. The water is drained by the Carquinez Strait, which flows into San Pablo Bay, a northern extension of San Francisco Bay, which then connects to the Pacific Ocean via the Golden Gate strait.
The Channel Islands are located off the Southern coast, while the Farallon Islands lie west of San Francisco
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The Sierra Nevada (Spanish for “snowy range”) includes the highest peak in the contiguous 48 states, Mount Whitney, at 14,505 feet (4,421 m). The range embraces Yosemite Valley, famous for its glacially carved domes, and Sequoia National Park, home to the giant sequoia trees, the largest living organisms on Earth, and the deep freshwater lake, Lake Tahoe, the largest lake in the state by volume.
To the east of the Sierra Nevada are Owens Valley and Mono Lake, an essential migratory bird habitat. In the western part of the state is Clear Lake, the largest freshwater lake by area entirely in California. Though Lake Tahoe is larger, it is divided by the California/Nevada border. The Sierra Nevada falls to Arctic temperatures in winter and has several dozen small glaciers, including Palisade Glacier, the southernmost glacier in the United States.