California is the 31st state of the United States of America, admitted to the Union on September 9, 1850.

The third largest state in the Union, 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 stand of 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. The nickname also suggests the state’s golden fields and sunshine.

Following are California’s major urban centers, in order of population (US Census 2006 estimates).

• Los Angeles, founded in 1781 as a Spanish pueblo, passed Chicago as the nation’s second largest city by the time of its bicentennial year in 1981.
• San Diego, the seat of San Diego County, is an important naval base and commercial port that serves as the major trade center of the Imperial Valley to the East.
• San Jose, the seat of Santa Clara County at the heart of Silicon Valley, is one of the most important manufacturing centers in the state.
• San Francisco, the "city by the Golden Gate", was California’s largest city from gold rush days in the 1850s until the early 1920s, when Los Angeles passed it in population. The city holds an influence in the United States in finance, international trade, and culture far greater than other cities of similar size.
• Long Beach is a major seaport in Los Angeles County;
• Fresno, the seat of Fresno County.
• Sacramento is the seat of Sacramento County and the state capital. In addition to serving as an administrative center, it is a major commercial and manufacturing city.
• Oakland, the seat of Alameda County, is an important port and manufacturing city.
• Santa Ana, the seat of Orange County.
• Anaheim, an industrial center in Orange County, is known for its theme parks.
• Bakersfield, the seat of Kern County, is a major food-processing center in the Central Valley.
• Riverside, the seat of Riverside County.