California (/ˌkælɨˈfɔrnjə/) is a state located on the West Coast of the United States. It is the most populous U.S. state, home to 1 out of 8 Americans, and is the third largest state by area (after Alaska and Texas). It is home to the nation's second and fifth largest census statistical areas (Greater Los Angeles area and San Francisco Bay Area, respectively), and eight of the nation's 50 most populated cities (Los Angeles, San Diego, San Jose, San Francisco, Fresno, Sacramento, Long Beach, and Oakland). The capital city is Sacramento.

California is bordered by Oregon to the north, Nevada to the east, and Arizona to the southeast. California is also bordered by Baja California, a state of Mexico, to the south. California's diverse geography ranges from the Pacific Coast in the west, to the Sierra Nevada in the east – 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 and lowest points in the contiguous United States (Mount Whitney and Death Valley), and has the 3rd longest coastline of all states (after Alaska and Florida). Earthquakes are a common occurrence due to the state's location along the Pacific Ring of Fire: about 37,000 are recorded annually.

The name California once referred to a large area of North America claimed by Spain that included much of the modern-day Southwestern United States and the Baja California peninsula. Beginning in the late 18th century, the area known as Alta California, comprising the California territory north of the Baja Peninsula, was colonized by the Spanish Empire as part of New Spain. In 1821, Alta California became a part of Mexico following its successful war for independence. Shortly after the beginning of the Mexican-American War in 1846, a group of American settlers in Sonoma declared an independent California Republic in Alta California. Though its existence was short-lived, its flag became the precursor for California's current state flag. American victory in the war led to the Treaty of Guadalupe Hidalgo, in which Mexico ceded Alta California to the United States. Western areas of Alta California became the state of California, which was admitted as the 31st state on September 9, 1850.

The California Gold Rush beginning in 1848 led to dramatic social and demographic change, with large scale immigration from the U.S. and abroad and an accompanying economic boom. Key developments in the early 20th century included the emergence of Los Angeles as the center of the American entertainment industry, and the growth of a large, state-wide tourism sector. The late 20th century saw the development of the technology and information sectors, punctuated by the growth of Silicon Valley (part of the San Francisco Bay Area). California's prosperous agricultural industry also emerged; at least half of the fresh fruit produced in the United States are now cultivated in California, and the state also leads in the production of vegetables. Other important contributors to its economy include aerospace, education, and manufacturing. If California were a country, as of 2012 it would have been the 9th largest economy in the world and the 34th most populous nation.

The first inhabitants

Settled by successive waves of arrivals during the last 10,000 years (although increasing numbers of pre-Clovis finds around the Americas indicates humans may have arrived up to 40,000 years earlier), California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. Various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. Most of these peoples were parts of larger ethno-linguistic groups spread across the modern Mexican-USA border and California's borders with other states, including speakers of Uto-Aztecan, Athabaskan, and Salishan languages. 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.

Colonial and Spanish periods

The first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. 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. The first Asians to set foot on what would be the United States occurred in 1587, when Filipino sailors arrived in Spanish ships at Morro Bay. Sebastián Vizcaíno explored and mapped the coast of California in 1602 for New Spain.

Despite the on-the-ground explorations of California in the 16th century, Rodríguez's idea of California as an island persisted. That depiction appeared on many European maps well into the 18th century.

After the Portolà expedition of 1769–70, Spanish missionaries began setting up 21 California Missions on or near the coast of Alta (Upper) California, beginning in San Diego. During the same period, Spanish military forces built several forts (presidios) and three small towns (pueblos). The San Francisco Mission grew into the city of San Francisco, and two of the pueblos grew into the cities of Los Angeles and San Jose. Several other smaller cities and towns also sprang up surrounding the various Spanish missions and pueblos, which remain to this day.

The Spanish colonization began the genocide of the indigenous Californian peoples, decimating their numbers through epidemics of various diseases for which the indigenous peoples had no natural immunity, such as measles and diphtheria. The establishment of the Spanish systems of government and social structure, which the Spanish settlers had brought with them, also technologically and culturally overwhelmed the societies of the earlier indigenous peoples.

During this same period, Russian ships also explored along the California coast and in 1812 established a trading post at Fort Ross. Russia's early 19th-century coastal settlements in California were positioned just north of the northernmost edge of the area of Spanish settlement in San Francisco Bay, and were the southernmost Russian settlements in North America. The Russian settlements associated with Fort Ross were spread over an area stretching from Point Arena to Tomales Bay.

California under Mexican rule

In 1821, the Mexican War of Independence gave Mexico (including California) independence from Spain. For the next 25 years Alta California remained as a remote, sparsely populated, northwestern administrative district of the newly independent country of Mexico.

Cattle ranches, or ranchos, emerged as the dominant institutions of Mexican California. Soon after Mexican independence from Spain, the chain of missions became the property of the Mexican government and were secularized by 1834. The ranchos developed under ownership by Californios (Spanish-speaking Californians) who had received land grants, and traded cowhides and tallow with Boston merchants.

From the 1820s, trappers and settlers from the United States and the future Canada arrived in Northern California. These new arrivals used the Siskiyou Trail, California Trail, Oregon Trail and Old Spanish Trail to cross the rugged mountains and harsh deserts in and surrounding California.

The early government of the newly independent Mexico was highly unstable, and in a reflection of this, from 1831 onwards, California also experienced a series of armed disputes, both between regional areas, and also revolts against the central Mexican government. During this tumultuous political period Juan Bautista Alvarado was able to secure the governorship from 1836 - 1842. The military action which first brought Alvarado to power, had momentarily declared California to be an independent state, and had been aided by American and British residents of California, including Isaac Graham. In 1840, one hundred of those residents who did not have passports were arrested, leading to the Graham affair.

One of the largest ranchers in California was John Marsh. After failing to obtain justice against squatters on his land from the Mexican courts, he determined that California should become part of the United States. Marsh conducted a letter-writing campaign espousing the California climate, soil and other reasons to settle there, as well as the best route to follow, which became known as "Marsh's route." His letters were read, reread, passed around, and printed in newspapers throughout the country, and started the first wagon trains rolling to California. He invited immigrants to stay on his ranch until they could get settled, and assisted in their obtaining passports.

After ushering in the period of organized emigration to California, Marsh helped end the rule of the last Mexican governor of California, thereby paving the way to California's ultimate acquisition by the United States.

California Republic and American invasion

In 1846, a group of American settlers in and around Sonoma 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. The Republic's only president was William B. Ide, who played a pivotal role during the Bear Flag Revolt. This revolt by American settlers served as a prelude to the later American military invasion of California, and was closely coordinated with nearby American military commanders.

The California Republic was short lived; the same year marked the outbreak of the Mexican–American War (1846–48). 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 United States forces. After a series of defensive battles in Southern California, the Treaty of Cahuenga was signed by the Californios on January 13, 1847, securing American control in California.

Early American statehood period

Following the Treaty of Guadalupe Hidalgo that ended the war, the Western-most portion of the old Mexican territory of Alta California, soon became the American state of California, and the remainder of the old territory was then subdivided into the new American Territories of Arizona, Nevada, Colorado and Utah. The lightly populated and arid lower region of old Baja California remained as a part of Mexico. In 1846, the total settler population of the Western part of the old Alta California had been estimated to be no more than 8,000, plus about 100,000 Native Americans down from about 300,000 before Hispanic settlement in 1769.

In 1848, only one week before the official American annexation of the area, gold was discovered in California, this being an event which was to forever alter both the state's demographics, and its finances. Soon afterwards, a massive influx in immigration into the area resulted, as prospectors and miners arrived by the thousands. The population burgeoned with United States citizens, Europeans, Chinese and other immigrants during the great California Gold Rush. By the time of California's application to the US Congress for statehood in 1850, the settler population of California had multiplied to 100,000. By 1854 over 300,000 settlers had come. Between 1847 and 1870, the population of San Francisco increased from 500 to 150,000. California was suddenly no longer a sparsely populated backwater, but seemingly overnight it had grown into a major US population center.

The seat of government for California under Spanish and later Mexican rule had been located in Monterey from 1777 until 1845. Pio Pico, last Mexican governor of Alta California, had briefly moved the capital to Los Angeles in 1845. The United States consulate had also been located in Monterey, under consul Thomas O. Larkin.

In 1849, a state Constitutional Convention was first held in Monterey. Among the first tasks of the Convention was a decision on a location for the new state capital. The first full 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 1862 when legislative sessions were held in San Francisco due to flooding in Sacramento.

Once the state's Constitutional Convention had finalized its state constitution, it applied to the US Congress for admission to statehood. On September 9, 1850, as part of the Compromise of 1850, California was officially admitted into the United States as an undivided free state. Its status as a 'free state' prevented the expansion of slavery to the Pacific Coast, which question was then a foremost concern for the pre-Civil War US Congress. Within the state of California, Sep 9 remains as an annually celebrated legal holiday known as California Admission Day.

During the American Civil War (1861–1865), California was able to send gold shipments eastwards to Washington in support of the Union cause, however due to the existence of a large contingent of pro-South sympathasizers within the state, the state was not able to muster any full military regiments to send eastwards to officially serve in the Union war effort. Still several smaller military units within the Union army were unofficially associated with the state of California, such as the "California 100 Company", due to a majority of their members being from California.

At the time of California's admission into the Union, travel between California and the rest of the continental United States had been a time consuming and dangerous feat. Nineteen years afterwards, and shortly after the conclusion of the Civil War, (in 1869) a more direct connection was developed with the completion of the First Transcontinental Railroad at Promontory Summit, Utah. Once completed, hundreds of thousands of United States citizens were enabled to easily migrate Westwards into the state.

Upon their arrival in California, the new Californians were able to discover that if irrigated during the dry summer months, that much of California 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.

Indigenous peoples under early American administration

Under earlier Spanish and Mexican rule, California's original native population had precipitously declined, above all, from Eurasian diseases to which the indigenous people of California had not yet developed a natural immunity. Under its new American administration, California's harsh governmental policies towards its own indigenous people did not improve. As in other American states, many of the native inhabitants were soon forcibly removed from their lands by incoming American settlers such as miners, ranchers, and farmers. Although California had entered the American union as a free state, the "loitering or orphaned Indians" were de facto enslaved by their new Anglo-American masters under the 1853 Act for the Government and Protection of Indians. There were also massacres in which hundreds of indigenous people were killed.

Between 1850 and 1860, the California state government paid around 1.5 million dollars (some 250,000 of which was reimbursed by the federal government) to hire militias whose purpose was to protect settlers from the indigenous populations. In later decades, the native population was placed in reservations and rancherias, which were often small and isolated and without enough natural resources or funding from the government to sustain the populations living on them. As a result, the rise of California was a calamity for the native inhabitants. Several scholars and Native American activists, including Benjamin Madley and Ed Castillo, have described the actions of the California government as a genocide.

20th century

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 1940, the Census Bureau reported California's population as 6.0% Hispanic, 2.4% Asian, and 89.5% non-Hispanic white.

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. California manufactured 8.7 percent of total United States military armaments produced during World War II, ranking third (behind New York and Michigan) among the 48 states. California however easily ranked 1st, in production of Military Ships during the war (transport, cargo, [Merchant Ships] such as Liberty ships, Victory ships, and Warships) at drydock facilities in San Diego, Los Angeles, and the San Francisco Bay Area. After World War II, California's economy greatly expanded due to strong aerospace and defense industries, whose size decreased following the end of the Cold War. 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 regarded as a world center of the entertainment and music industries, of technology, engineering, and the aerospace industry, and as the United States center of agricultural production. Just before the "Dot Com Bust" California had the 5th largest economy in the world among nations. Yet since 1991, and starting in the late 1980s in Southern California, California has seen a net loss of domestic migrants most years. This is often referred to by the media as the California exodus.

During the 20th century, two great disasters happened in California. The 1906 San Francisco earthquake and 1928 St. Francis Dam flood remain the deadliest in U.S history.

The culture of California is a Western culture and most clearly has its modern roots in the culture of the United States, but also, historically, many Hispanic influences. As a border and coastal state, Californian culture has been greatly influenced by several large immigrant populations, especially those from Latin America and Asia.^{[not in citation given]}

California has long been a subject of interest in the public mind and has often been promoted by its boosters as a kind of paradise. In the early 20th century, fueled by the efforts of state and local boosters, many Americans saw the Golden State as an ideal resort destination, sunny and dry all year round with easy access to the ocean and mountains. In the 1960s, popular music groups such as The Beach Boys promoted the image of Californians as laid-back, tanned beach-goers.

The California Gold Rush of the 1850s is still seen as a symbol of California's economic style, which tends to generate technology, social, entertainment, and economic fads and booms and related busts.

Religion

The largest religious denominations by number of adherents as a percentage of California's population in 2014 were the Catholic Church with 28 percent, Evangelical Protestants with 20 percent, and Mainline Protestants with 10 percent. Together, all kinds of Protestants accounted for 32 percent. Those unaffiliated with any religion represented 27 percent of the population. The breakdown of other religions is 1% Muslim, 2% Hindu and 2% Buddhist. This is a change from 2008, when the population identified their religion with the Catholic Church with 31 percent; Evangelical Protestants with 18 percent; and Mainline Protestants with 14 percent. In 2008, those unaffiliated with any religion represented 21 percent of the population. The breakdown of other religions in 2008 was 0.5% Muslim, 1% Hindu and 2% Buddhist. The American Jewish Year Book placed the total Jewish population of California at about 1,194,190 in 2006. According to the Association of Religion Data Archives (ARDA) the largest denominations by adherents in 2010 were the Roman Catholic Church with 10,233,334; The Church of Jesus Christ of Latter-day Saints with 763,818; and the Southern Baptist Convention with 489,953.

The first priests to come to California were Roman Catholic missionaries from Spain. Roman Catholics founded 21 missions along the California coast, as well as the cities of Los Angeles and San Francisco. California continues to have a large Roman Catholic population due to the large numbers of Mexicans and Central Americans living within its borders. California has twelve dioceses and two archdioceses, the Archdiocese of Los Angeles and the Archdiocese of San Francisco, the former being the largest archdiocese in the United States.

A Pew Research Center survey revealed that California is somewhat less religious than the rest of the US: 62 percent of Californians say they are "absolutely certain" of their belief in God, while in the nation 71 percent say so. The survey also revealed 48 percent of Californians say religion is "very important", compared to 56 percent nationally.

Sports

California has twenty major professional sports league franchises, far more than any other state. The San Francisco Bay Area has seven major league teams spread in its three major cities: San Francisco, San Jose, and Oakland. While the Greater Los Angeles Area is home to ten major league franchises. San Diego and Sacramento each have one major league team. The NFL Super Bowl has been hosted in California 11 times at four different stadiums: Los Angeles Memorial Coliseum, the Rose Bowl, Stanford Stadium, and San Diego's Qualcomm Stadium. A twelfth, Super Bowl 50, was held at Levi's Stadium in Santa Clara on February 7, 2016.

California has long had many respected collegiate sports programs. California is home to the oldest college bowl game, the annual Rose Bowl, among others.

California is the only US state to have hosted both the Summer and Winter Olympics. The 1932 and 1984 Summer Olympics were held in Los Angeles. Squaw Valley Ski Resort in the Lake Tahoe region hosted the 1960 Winter Olympics. Los Angeles will host the 2028 Summer Olympics, marking the fourth time California hosts the Olympic Games. Multiple games during the 1994 FIFA World Cup took place in California, with the Rose Bowl hosting eight matches including the final, while Stanford Stadium hosted six matches.

Below is a list of major league sports teams in California:

Education

Public secondary education consists of high schools that teach elective courses in trades, languages, and liberal arts with tracks for gifted, college-bound and industrial arts students. California's public educational system is supported by a unique constitutional amendment that requires a minimum annual funding level for grades K–12 and community colleges that grows with the economy and student enrollment figures.

California had over 6.2 million school students in the 2005–06 school year. Funding and staffing levels in California schools lag behind other states. In expenditure per pupil, California ranked 29th (of the 50 states and the District of Columbia) in 2005–06. In teaching staff expenditure per pupil, California ranked 49th of 51. In overall teacher-pupil ratio, California was also 49th, with 21 students per teacher. Only Arizona and Utah were lower.

A 2007 study concluded that California's public school system was "broken" in that it suffered from over-regulation.

California's public postsecondary education offers three separate systems:

• The research university system in the state is the University of California (UC), a public university system. As of fall 2011, the University of California had a combined student body of 234,464 students. There are ten general UC campuses, and a number of specialized campuses in the UC system, as the UC San Francisco, which is entirely dedicated to graduate education in health care, and is home to the UCSF Medical Center, the highest ranked hospital in California. The system was originally intended to accept the top one-eighth of California high school students, but several of the schools have become even more selective. The UC system was originally given exclusive authority in awarding Ph.Ds, but this has since changed and the CSU is also able to award several Doctoral degrees.
• The California State University (CSU) system has almost 430,000 students. The CSU was originally intended to accept the top one-third of California high school students, but several of the schools have become much more selective. The CSU was originally set up to award only bachelor's and master's degrees, but has since been granted the authority to award several Doctoral degrees.
• The California Community Colleges System provides lower division coursework as well as basic skills and workforce training. It is the largest network of higher education in the US, composed of 112 colleges serving a student population of over 2.6 million.

California is also home to such notable private universities as Stanford University, the University of Southern California, the California Institute of Technology, and the Claremont Colleges. California has hundreds of other private colleges and universities, including many religious and special-purpose institutions.

Twin region

California has a twinning arrangement with the region of Catalonia in Spain Catalonia is made up of four Spanish provinces: Barcelona, Girona, Lleida, and Tarragona.

California is the 3rd largest state in the United States in area, after Alaska and Texas. California is often geographically bisected into two regions, Southern California, comprising the 10 southernmost counties, and Northern California, comprising the 48 northernmost counties. It is bordered by Oregon to the north, Nevada to the east and northeast, Arizona to the southeast, the Pacific Ocean to the west and it shares an international border with the Mexican state of Baja California to the south.

In the middle of the state lies the California Central Valley, bounded by the Sierra Nevada in the east, the coastal mountain ranges in the west, the Cascade Range to the north and by the Tehachapi Mountains in the south. The Central Valley is California's productive agricultural heartland.

Divided in two by the Sacramento-San Joaquin River Delta, the northern portion, the Sacramento Valley serves as the watershed of the Sacramento River, while the southern portion, the San Joaquin Valley is the watershed for the San Joaquin River. Both valleys derive their names from the rivers that flow through them. With dredging, the Sacramento and the San Joaquin Rivers have remained deep enough for several inland cities to be seaports.

The Sacramento-San Joaquin River Delta is a critical water supply hub for the state. Water is diverted from the delta and through an extensive network of pumps and canals that traverse nearly the length of the state, to the Central Valley and the State Water Projects and other needs. Water from the Delta provides drinking water for nearly 23 million people, almost two-thirds of the state's population as well as water for farmers on the west side of the San Joaquin Valley.

Suisun Bay lies at the confluence of the Sacramento and San Joaquin Rivers. The water is drained by the Carquinez Strait, which flows into San Pablo Bay, a northern extension of San Francisco Bay, which then connects to the Pacific Ocean via the Golden Gate strait.

The Channel Islands are located off the Southern coast, while the Farallon Islands lie west of San Francisco.

The Sierra Nevada (Spanish for "snowy range") includes the highest peak in the contiguous 48 states, Mount Whitney, at 14,505 feet (4,421 m). The range embraces Yosemite Valley, famous for its glacially carved domes, and Sequoia National Park, home to the giant sequoia trees, the largest living organisms on Earth, and the deep freshwater lake, Lake Tahoe, the largest lake in the state by volume.

To the east of the Sierra Nevada are Owens Valley and Mono Lake, an essential migratory bird habitat. In the western part of the state is Clear Lake, the largest freshwater lake by area entirely in California. Though Lake Tahoe is larger, it is divided by the California/Nevada border. The Sierra Nevada falls to Arctic temperatures in winter and has several dozen small glaciers, including Palisade Glacier, the southernmost glacier in the United States.

About 45 percent of the state's total surface area is covered by forests, and California's diversity of pine species is unmatched by any other state. California contains more forestland than any other state except Alaska. Many of the trees in the California White Mountains are the oldest in the world; an individual bristlecone pine is over 5,000 years old.

In the south is a large inland salt lake, the Salton Sea. The south-central desert is called the Mojave; to the northeast of the Mojave lies Death Valley, which contains the lowest and hottest place in North America, the Badwater Basin at −279 feet (−85 m). The horizontal distance from the bottom of Death Valley to the top of Mount Whitney is less than 90 miles (140 km). Indeed, almost all of southeastern California is arid, hot desert, with routine extreme high temperatures during the summer. The southeastern border of California with Arizona is entirely formed by the Colorado River, from which the southern part of the state gets about half of its water.

A majority of California's cities are located in either the San Francisco Bay Area or the Sacramento metropolitan area in Northern California; or the Los Angeles area, the Riverside-San Bernardino-Inland Empire, or the San Diego metropolitan area in Southern California. The Los Angeles Area, the Bay Area, and the San Diego metropolitan area are among several major metropolitan areas along the California coast.

As part of the Ring of Fire, California is subject to tsunamis, floods, droughts, Santa Ana winds, wildfires, landslides on steep terrain, and has several volcanoes. It has many earthquakes due to several faults running through the state, in particular the San Andreas Fault. About 37,000 earthquakes are recorded each year, but most are too small to be felt.

Climate

Although most of the state has a Mediterranean climate, due to the state's large size, the climate ranges from subarctic to subtropical. The cool California Current offshore often creates summer fog near the coast. Farther inland, there are colder winters and hotter summers. The maritime moderation results in the shoreline summertime temperatures of Los Angeles and San Francisco being the coolest of all major metropolitan areas of the United States and uniquely cool compared to areas on the same latitude in the interior and on the east coast of the North American continent. Even the San Diego shoreline bordering Mexico is cooler in summer than most areas in the contiguous United States. Just a few miles inland, summer temperature extremes are significantly higher, with downtown Los Angeles being several degrees warmer than at the coast. The same microclimate phenomenon is seen in the climate of the Bay Area, where areas sheltered from the sea experience significantly hotter summers than nearby areas that are close to the ocean.

Northern parts of the state have more rain than the south. California's mountain ranges also influence the climate: some of the rainiest parts of the state are west-facing mountain slopes. Northwestern California has a temperate climate, and the Central Valley has a Mediterranean climate but with greater temperature extremes than the coast. The high mountains, including the Sierra Nevada, have an alpine climate with snow in winter and mild to moderate heat in summer.

California's mountains produce rain shadows on the eastern side, creating extensive deserts. The higher elevation deserts of eastern California have hot summers and cold winters, while the low deserts east of the Southern California mountains have hot summers and nearly frostless mild winters. Death Valley, a desert with large expanses below sea level, is considered the hottest location in the world; the highest temperature in the world, 134 °F (56.7 °C), was recorded there on July 10, 1913. The lowest temperature in California was −45 °F (−43 °C) in 1937 in Boca.

The table below lists average temperatures for August and December in a selection of places throughout the state; some highly populated and some not. This includes the relatively cool summers of the Humboldt Bay region around Eureka, the extreme heat of Death Valley, and the mountain climate of Mammoth in the Sierra Nevadas.

Ecology

California is one of the richest and most diverse parts of the world, and includes some of the most endangered ecological communities. California is part of the Nearctic ecozone and spans a number of terrestrial ecoregions.

California's large number of endemic species includes relict species, which have died out elsewhere, such as the Catalina ironwood (Lyonothamnus floribundus). Many other endemics originated through differentiation or adaptive radiation, whereby multiple species develop from a common ancestor to take advantage of diverse ecological conditions such as the California lilac (Ceanothus). Many California endemics have become endangered, as urbanization, logging, overgrazing, and the introduction of exotic species have encroached on their habitat.

Flora and fauna

California boasts several superlatives in its collection of flora: the largest trees, the tallest trees, and the oldest trees. California's native grasses are perennial plants. After European contact, these were generally replaced by invasive species of European annual grasses; and, in modern times, California's hills turn a characteristic golden-brown in summer.

Because California has the greatest diversity of climate and terrain, the state has six life zones which are the lower Sonoran (desert); upper Sonoran (foothill regions and some coastal lands), transition (coastal areas and moist northeastern counties); and the Canadian, Hudsonian, and Arctic Zones, comprising the state's highest elevations.

Plant life in the dry climate of the lower Sonoran zone contains a diversity of native cactus, mesquite, and paloverde. The Joshua tree is found in the Mojave Desert. Flowering plants include the dwarf desert poppy and a variety of asters. Fremont cottonwood and valley oak thrive in the Central Valley. The upper Sonoran zone includes the chaparral belt, characterized by forests of small shrubs, stunted trees, and herbaceous plants. Nemophila, mint, Phacelia, Viola, and the California poppy (Eschscholzia californica) – the state flower – also flourish in this zone, along with the lupine, more species of which occur here than anywhere else in the world.

The transition zone includes most of California's forests with the redwood (Sequoia sempervirens) and the "big tree" or giant sequoia (Sequoiadendron giganteum), among the oldest living things on earth (some are said to have lived at least 4,000 years). Tanbark oak, California laurel, sugar pine, madrona, broad-leaved maple, and Douglas-fir also grow here. Forest floors are covered with swordfern, alumnroot, barrenwort, and trillium, and there are thickets of huckleberry, azalea, elder, and wild currant. Characteristic wild flowers include varieties of mariposa, tulip, and tiger and leopard lilies.

The high elevations of the Canadian zone allow the Jeffrey pine, red fir, and lodgepole pine to thrive. Brushy areas are abundant with dwarf manzanita and ceanothus; the unique Sierra puffball is also found here. Right below the timberline, in the Hudsonian zone, the whitebark, foxtail, and silver pines grow. At about 10,500 feet (3,200 m), begins the Arctic zone, a treeless region whose flora include a number of wildflowers, including Sierra primrose, yellow columbine, alpine buttercup, and alpine shooting star.

Common plants that have been introduced to the state include the eucalyptus, acacia, pepper tree, geranium, and Scotch broom. The species that are federally classified as endangered are the Contra Costa wallflower, Antioch Dunes evening primrose, Solano grass, San Clemente Island larkspur, salt marsh bird's beak, McDonald's rock-cress, and Santa Barbara Island liveforever. As of December 1997, 85 plant species were listed as threatened or endangered.

In the deserts of the lower Sonoran zone, the mammals include the jackrabbit, kangaroo rat, squirrel, and opossum. Common birds include the owl, roadrunner, cactus wren, and various species of hawk. The area's reptilian life include the sidewinder viper, desert tortoise, and horned toad. The upper Sonoran zone boasts mammals such as the antelope, brown-footed woodrat, and ring-tailed cat. Birds unique to this zone are the California thrasher, bushtit, and California condor.

In the transition zone, there are Colombian black-tailed deer, black bears, gray foxes, cougars, bobcats, and Roosevelt elk. Reptiles such as the garter snakes and rattlesnakes inhabit the zone. In addition, amphibians such as the water puppy and redwood salamander are common too. Birds such as the kingfisher, chickadee, towhee, and hummingbird thrive here as well.

The Canadian zone mammals include the mountain weasel, snowshoe hare, and several species of chipmunks. Conspicuous birds include the blue-fronted jay, Sierra chickadee. Sierra hermit thrush, water ouzel, and Townsend's solitaire. As one ascends into the Hudsonian zone, birds become scarcer. While the Sierra rosy finch is the only bird native to the high Arctic region, other bird species such as the hummingbird and Clark's nutcracker. Principal mammals found in this region include the Sierra coney, white-tailed jackrabbit, and the bighorn sheep. As of April 2003, the bighorn sheep was listed as endangered by the US Fish and Wildlife Service. The fauna found throughout several zones are the mule deer, coyote, mountain lion, northern flicker, and several species of hawk and sparrow.

Aquatic life in California thrives, from the state's mountain lakes and streams to the rocky Pacific coastline. Numerous trout species are found, among them rainbow, golden, and cutthroat. Migratory species of salmon are common as well. Deep-sea life forms include sea bass, yellowfin tuna, barracuda, and several types of whale. Native to the cliffs of northern California are seals, sea lions, and many types of shorebirds, including migratory species.

As of April 2003, 118 California animals were on the federal endangered list; 181 plants were listed as endangered or threatened. Endangered animals include the San Joaquin kitfox, Point Arena mountain beaver, Pacific pocket mouse, salt marsh harvest mouse, Morro Bay kangaroo rat (and five other species of kangaroo rat), Amargosa vole, California least tern, California condor, loggerhead shrike, San Clemente sage sparrow, San Francisco garter snake, five species of salamander, three species of chub, and two species of pupfish. Eleven butterflies are also endangered and two that are threatened are on the federal list. Among threatened animals are the coastal California gnatcatcher, Paiute cutthroat trout, southern sea otter, and northern spotted owl. California has a total of 290,821 acres (1,176.91 km²) of National Wildlife Refuges. As of September 2010, 123 California animals were listed as either endangered or threatened on the federal list provided by the US Fish & Wildlife Service. Also, as of the same year, 178 species of California plants were listed either as endangered or threatened on this federal list.

Rivers

The vast majority of rivers in California are dammed as part of two massive water projects: the Central Valley Project, providing water to the agricultural central valley, and the California State Water Project diverting water from northern to southern California. The state's coasts, rivers, and other bodies of water are regulated by the California Coastal Commission.

The two most prominent rivers within California are the Sacramento River and the San Joaquin River, which drain the Central Valley and the west slope of the Sierra Nevada and flow to the Pacific Ocean through San Francisco Bay. Several major tributaries feed into the Sacramento and the San Joaquin, including the Pit River, the Tuolumne River, and the Feather River.

The Eel River and Salinas River each drain portions of the California coast, north and south of San Francisco Bay, respectively, and the Eel River is the largest river in the state to remain in its natural un-dammed state. The Mojave River is the primary watercourse in the Mojave Desert, and the Santa Ana River drains much of the Transverse Ranges as it bisects Southern California. Some other important rivers are the Klamath River and the Trinity River in the far north coast, and the Colorado River on the southeast border with Arizona.

Regions