California, the most populous of the states, is the national leader in agriculture, commercial fishing, and motor vehicle ownership. It ranks first in manufacturing and third in land area and oil production. In fact, one in every eight Americans is a Californian.

The heart of the state is the fertile Central Valley, fenced in by two long North-South mountain ranges: the Sierra Nevada (on the East) and the Coast Range. Several small forested ranges of the Klamath Mountains cover the Northwestern corner of the state, while below the Coast Range are the Los Angeles Ranges, and below these, the San Diego Ranges. More than 40 percent of the land is forested. Other important land areas are the Cascade Valley Mountains extending northward from the Central Valley and the Basin and Range region, which are bordered on the Southeast by the Mojave and Colorado deserts.

Both the highest mountain peak in the conterminous United States, Mt. Whitney (14,494 feet) and Death Valley, the lowest point in the hemisphere (282 feet below sea level) can be seen from Dante's View, 5,475 feet high and about 3 miles East of that Death Valley. The only active volcano in the conterminous states is 10,457 -foot Lassen Peak at Lassen Volcanic National Park, in the Northwest corner of the state. Two island groups lie off the coast: the Santa Barbara (or Channel) Islands, consisting of eight major islands 20 to 60 miles from the Southern Mainland, and the six small rugged Farallon Islands, about 30 miles west of San Francisco. Great extremes mark the climate, with many areas enjoying generally mild and sunny weather, partially befouled in urban areas by palls of smog.
There were about 130,000 Indians living in the California region when Juan Rodriguez Carrillo, a Portuguese in Spanish employ, discovered it in 1542. English interest in the area began with Sir Frances Drake, who claimed (1579) it for Queen Elizabeth I. But the first permanent settlement was made by Spaniards, who established 21 missions Northward along the coast from San Diego (1769) to Sonoma (1823). In 1812, Russian fur traders from Alaska came down and established Fort Ross on the state's Northern coast, but they did not prevail. In 1822, after Mexico won its independence from Spain, California became a Mexican province, and it’s social, economic, and political life was centered on large cattle ranches, also known as Ranchos. The first organized group of American settlers came to the region by land in 1841; the United States offered to buy province, but Mexico refused to sell. U.S. forces occupied the area early in the Mexican War, with Mexico formally ceding it claim in 1848.