California, state in the western United States, bordering the Pacific Ocean. The third largest state in the United States, California covers an area of great physical diversity in which uplands dominate the landscape. The mountains, hills, ridges, and peaks of California flank the coastline, rise to nearly 4,600 m (15,000 ft) in the towering Sierra Nevada, encircle the great fertile basin of the Central Valley, and separate the desert into innumerable basins. However, despite the physical dominance and economic value of the uplands, California's urban areas and economic production are concentrated in the valleys and lowlands, such as in the huge metropolitan region centered on Los Angeles, the state's largest and the nation's second largest city. Manufacturing, agriculture, and related activities are the principal sources of income. They are based in large part on the state's wealth of natural resources, its productive farmlands, its large and highly skilled labor force, and its ability to market its output both at home and abroad

California's size, complexity, and economic productivity make it preeminently a state of superlatives. It has the lowest point in the country, in Death Valley, and the highest U.S. peak outside of Alaska, Mount Whitney. Among the 50 states it has the greatest number of national parks and national forests, and the only stands of redwoods and giant sequoias. Its annual farm output is greater in value than that of any other state, and it leads the rest of the nation in the production of many crops. It is the leading state in volume of annual construction and manufacturing. California has more people than any other state and more automobiles, more civil aircraft, and more students enrolled in universities and colleges. 

Between the late 1940s and late 1980s the rate of growth and actual growth of California's population and economy were phenomenal compared with other states. However, this growth also gave rise to, or aggravated, several major problems that now face Californians. Much of the growth occurred in the dry south where water shortages must be offset by vast, expensive public projects delivering water from the wetter north. Urban centers extended outward into good farmland, forever removing it from food production. In addition, as population continues to increase, California is faced with the problem of providing its inhabitants with more schools, hospitals, water, highways, recreational facilities, and other services.

The name California was first used to designate the region by the Spanish expedition led by Juan Rodríguez Cabrillo, as it sailed northward along the coast from Mexico in 1542. The name itself was probably derived from a popular Spanish novel published in 1510 in which a fictional island paradise named California was described. The state's official nickname is the Golden State, referring to the gold rush, which played a central role in California's entry into the Union on September 9, 1850, as the 31st state. The nickname also suggests the state's golden fields and sunshine.