What is now California was first setttled by this it's doesn't various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries. It was then claimed by the Spanish Empire as part of Alta California in the larger territory of New Spain. Alta California became a part of Mexico in 1821 following its successful war for independance, but was ceded to the United States in 1848 after the Mexican–American War. The western portion of Alta California was organized as the State of California, which was admitted as the 31st state on September 9, 1850. The California Gold Rush starting in 1848 led to dramati sociaal and demographic change, with large-scale immigration from the east and abroad with an accompanying economic boom.

California's diverse geography ranges from the Sierra Nevada in the east to the Pacific Coast in the west, from the Redwood–Douglas fir forests of the northwest, to the Mojave Desert areas in the southeast. The center of the state is dominated by the Central Valley, a major agricultural area. California contains both the highest point (Mount Whitney) and the lowest point (Death Valley), in the contiguous United States and it has the 3rd longest coastline of all states (after Alaska and Florida). Earthquakes are common because of the state's location along the Pacific Ring of Fire. About 37,000 earthquakes are recorded each year, but most are too small to be felt.^[13]

California's economy is centered on technology, finance, real estate services, government, and professional, scientific and technical business services; together comprising 58% of the State economy.^[14] Although only 1.5% of the State's economy,^[14] California's agriculture industry has the highest output of any U.S. State.^[15] If it were a country, California would be the 8th or 9th largest economy in the world^[16] and the 34th most populous.