Settled by successive waves of arrivals during the last 10,000 years, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America; The Indigenous peoples of California included more than 70 distinct groups of Native Americans. Large, settled populations lived on the coast and hunted sea mammals, fished for salmon and gathered shellfish; groups in the interior hunted terrestrial game, and gathered nuts, acorns and berries. California groups also were diverse in their political organization with bands, tribes, villages, and on the resource-rich coasts, large chiefdoms, such as the Chumash, Pomo and Salinan. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups.
The first European to explore the coast as far north as the Russian River was the Portuguese Juan Rodríguez Cabrillo, in 1542, sailing for the Spanish Empire. Some 37 years later English explorer Francis Drake also explored and claimed an undefined portion of the California coast in 1579. Spanish traders made unintended visits with the Manila Galleons on their return trips from the Philippines beginning in 1565. Sebastián Vizcaíno explored and mapped the coast of California in 1602 for New Spain.
Spanish missionaries began setting up 21 California Missions along the coast of what became known as Alta California (Upper California), together with small towns and presidios. In 1821 the Mexican War of Independence gave Mexico (including California) independence from Spain; for the next 25 years, Alta California remained a remote northern province of the nation of Mexico. Cattle ranches, or ranchos, emerged as the dominant institutions of Mexican California. After Mexican independence from Spain, the chain of missions became the property of the Mexican government and were secularized by 1832. The ranchos developed under ownership by Californios (Spanish-speaking Californians) who had received land grants, and traded cowhides and tallow with Boston merchants.
Beginning in the 1820s, trappers and settlers from the U.S. and Canada began to arrive in Northern California, harbingers of the great changes that would later sweep the Mexican territory. These new arrivals used the Siskiyou Trail, California Trail, Oregon Trail and Old Spanish Trail to cross the rugged mountains and harsh deserts surrounding California. In this period, Imperial Russia explored the California coast and established a trading post at Fort Ross.
In 1846 settlers rebelled against Mexican rule during the Bear Flag Revolt. Afterwards, rebels raised the Bear Flag (featuring a bear, a star, a red stripe and the words "California Republic") at Sonoma.
“[We] overthrow a Government which has seized upon the property of the Missions for its individual aggrandizement; which has ruined and shamefully oppressed the laboring people of California.”—William Ide, Declaration from the Bear Flag Revolt
The Republic's first and only president was William B. Ide, who played a pivotal role during the Bear Flag Revolt. His term lasted 22 days and concluded when California was occupied by U.S. forces during the Mexican-American War.
The California Republic was short lived. The same year marked the outbreak of the Mexican-American War (1846–1848). When Commodore John D. Sloat of the United States Navy sailed into Monterey Bay and began the military occupation of California by the United States. Northern California capitulated in less than a month to the U.S. forces. After a series of defensive battles in Southern California, including The Siege of Los Angeles, the Battle of Dominguez Rancho, the Battle of San Pasqual, the Battle of Rio San Gabriel and the Battle of La Mesa, the Treaty of Cahuenga was signed by the Californios on January 13, 1847, securing American control in California. Following the Treaty of Guadalupe Hidalgo that ended the war, the region was divided between Mexico and the U.S.; the western territory of Alta California, was to become the U.S. state of California, and Arizona, Nevada, Colorado and Utah became U.S. Territories, while the lower region of California, the Baja Peninsula, remained in the possession of Mexico.
In 1848 the non-native population of California was estimated to be no more than 15,000. But after gold was discovered, the population burgeoned with U.S. citizens, Europeans and other immigrants during the great California Gold Rush. By 1854 over 300,000 settlers had come. On September 9, 1850, as part of the Compromise of 1850, California was admitted to the United States undivided as a free state, denying the expansion of slavery to the Pacific Coast.
The seat of government for California under Spanish and later Mexican rule was located at Monterey from 1777 until 1835, when Mexican authorities abandoned California, leaving their missions and military forts behind. In 1849 the Constitutional Convention was first held there. Among the duties was the task of determining the location for the new state capital. The first legislative sessions were held in San Jose (1850–1851). Subsequent locations included Vallejo (1852–1853), and nearby Benicia (1853–1854); these locations eventually proved to be inadequate as well. The capital has been located in Sacramento since 1854 with only a short break in 1861 when legislative sessions were held in San Francisco due to flooding in Sacramento.
Travel between California and the central and eastern parts of the U.S. was time consuming and dangerous. A more direct connection came in 1869 with the completion of the First Transcontinental Railroad through Donner Pass in the Sierra Nevada mountains. After this rail link was established, hundreds of thousands of U.S. citizens came west, where new Californians were discovering that land in the state, if irrigated during the dry summer months, was extremely well suited to fruit cultivation and agriculture in general. Vast expanses of wheat, other cereal crops, vegetable crops, cotton, and nut and fruit trees were grown (including oranges in Southern California), and the foundation was laid for the state's prodigious agricultural production in the Central Valley and elsewhere.
Migration to California accelerated during the early-20th century with the completion of major transcontinental highways like the Lincoln Highway and Route 66. In the period from 1900 to 1965, the population grew from fewer than one million to become the most populous state in the Union. In order to meet the population's needs, major engineering feats like the California and Los Angeles Aqueducts; the Oroville and Shasta Dams; and the Bay and Golden Gate Bridges were built across the state. The state government also adopted the California Master Plan for Higher Education in 1960 to develop a highly efficient system of public education.
Meanwhile, attracted to the mild Mediterranean climate, cheap land, and the state's wide variety of geography, filmmakers established the studio system in Hollywood in the 1920s. A couple of decades later, Stanford University and its Dean of Engineering Frederick Terman began encouraging faculty and graduates to stay in California instead of leaving the state, and develop a high-tech region in the area now known as Silicon Valley. As a result of these efforts, California is currently regarded as a world center of the entertainment and music industries, of technology and engineering businesses, and as the U.S. center of agricultural production.