California is a state located on the West Coast of the United States. It is the most populous U.S. state, with 38 million people, one in eight of the people who live in the U.S, and the third largest state by area (after Alaska and Texas). California is bordered by Oregon to the north, Nevada to the east, Arizona to the southeast, and the Mexican state of Baja California to the south. Alta California became a part of Mexico in 1821, 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 dramatic social 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).