Flag of the state of California, USA

California (/ˌkælɪˈfɔːrniə/) is a state in the Western United States that lies on the Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares an international border with the Mexican state of Baja California to the south. With almost 40 million residents across an area of 163,696 square miles (423,970 km2), it is the largest state by population, third-largest state by area and the largest state economy. Prior to European colonisation, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. European exploration in the 16th and 17th centuries led to the colonisation by the Spanish Empire. The area became a part of Mexico in 1821, as a result of its successful war for independence. Following the U.S. conquest of California, part of the Mexican-American War, California was ceded to the United States in 1848. The California gold rush started in 1848 and led to social and demographic changes, including the California genocide. It organised itself and was admitted as the 31st state in 1850 as a free state, following the Compromise of 1850. The Greater Los Angeles and San Francisco Bay Area areas are the nation's second- and fifth-most populous urban regions, with 19 million and 10 million residents respectively. Los Angeles is the state's most populous city and the nation's second-most. California's capital is Sacramento. Part of the Californias region of North America, the state's diverse geography ranges from the Pacific Coast and metropolitan areas in the west to the Sierra Nevada mountains in the east, and from the redwood and Douglas fir forests in the northwest to the Mojave Desert in the southeast. Two-thirds of the nation's earthquake risk lies in California. The Central Valley, a fertile agricultural area, dominates the state's centre. The large size of the state results in climates that vary from moist temperate rainforest in the north to arid desert in the interior, as well as snowy alpine in the mountains. Droughts and wildfires are an ongoing issue, while simultaneously, atmospheric rivers are turning increasingly prevalent and leading to intense flooding events—especially in the winter. The economy of California is the largest of any U.S. state, with an estimated 2024 gross state product of $4.172 trillion as of Q4 2024. It is the world's largest sub-national economy and, if it were an independant country, would be the fourth-largest economy in the world (putting it, as of 2025, behind Germany and ahead of Japan) when ranked by nominal GDP. The state's agricultural industry leads the nation in output, fuelled by its production of dairy, almonds, and grapes. With the busiest port in the country (Los Angeles), California plays a pivotal role in the global supply chain, hauling in about 40% of goods imported to the US. Noteable contributions to popular culture, ranging from entertainment, sports, music, and fashion, have their origins in California. Hollywood in Los Angeles is the centre of the U.S. film industry and one of the oldest and largest film industries in the world; profoundly influencing global entertainment since the 1920s. The San Francisco Bay's Silicon Valley is the centre of the global technology industry.