Riverside County, CA, is home to a population of 2.44 million people, of whom 89.8% are citizens. This county is included in the Riverside-San Bernardino-Ontario metropolitan statistical area, also known as the Inland Empire, and the Los Angeles-Long Beach Combined Statistical Area. It covers 7,208 square miles (18,670 km) in Southern California, stretching from the Los Angeles metropolitan area to the Arizona border. Geographically, the county is mostly desert in the central and eastern parts, but has a Mediterranean climate in the western part.
Most of Joshua Tree National Park is located in the county and it is home to 28 cities. Riverside County was formed in 1893 and named after the city of Riverside, the county seat. This city was founded in 1870 and received its name because of its location next to the Santa Ana River. The indigenous peoples of what is now Riverside County are the Luiseño, Cupeño and Cahuilla Indians. The Luiseño territory includes the Aguanga and Temecula basins, the Elsinore Depression and the eastern Santa Ana Mountains and south to San Diego County.
The territory of Cahuilla is located east and north of Luiseño, in the interior valleys, in the Santa Rosa and San Jacinto mountains and the Salton Sink Desert. The first European settlement in the county was a ranch or farm of the Saint Louis King Mission of France in the Luiseño village of Temescal. In 1819, Leandro Serrano was granted permission to occupy this land for grazing and agriculture purposes, and he established Rancho Temescal. Serrano was butler of San Antonio de Pala Assistance for the San Luis Rey Mission. In 1893, seventy percent of voters approved the formation of Riverside County. Voters chose the city of Riverside as the county seat by a wide margin.
Riverside County was officially formed on April 9th, when the Board of Commissioners presented the final ballot count. Riverside County was an important focal point of civil rights movements in the United States, especially for African-Americans living in Riverside and Mexican-Americans living in Coachella Valley. Cesar Chavez visited this area during his agricultural union struggle. The county has a diverse flora and fauna. Vegetative plant associations have a lot of desert flora, but there are also wooded areas within it. California's endemic blue oak, Quercus douglasii, is found in its southernmost part. In terms of demographics, 30.3% of its population is under 18 years old; 9.2% is between 18 and 24; 28.9% between 25 and 44; 18.9% between 45 and 64; and 12.7% aged 65 or over.
The median age is 33 years old. For every 100 women there are 99.1 men; for every 100 females age 18 or over there are 96.8 men. The municipal departments within Riverside County are Banning, Beaumont, Blythe, Calimesa, Cathedral City, Corona, Desert Hot Springs, Hemet, Indio, Menifee, Murrieta, Palm Springs and Riverside Community College. Amtrak trains stop at Riverside and Palm Springs; Amtrak California offers bus connections to San Joaquins at Riverside, Beaumont, Palm Springs, Thousand Palms, Indio, Moreno Valley, Perris Sun City and Hemet. Riverside County has 12 federally recognized Indian reservations linking it to Sandoval County in New Mexico; this is only second county in the United States with such a connection. However Sandoval County has two additional co-use areas shared between reserves. The largest universities in Riverside County by number of degrees awarded are University of California-Riverside (6,843 and 23.3%), Riverside City College (4992 and 17%) and Mt San Jacinto Community College District (3385 and 11.5%).
The Riverside County Sheriff provides judicial protection prison administration and forensic services for all of Riverside County. When California's initial 27 counties were established in 1850 this area was divided between Los Angeles County and San Diego County. This chart shows the stock breakdown of major industries for residents of Riverside County although some may live here but work elsewhere. Riverside County is organized as a general law county under California Government Code provisions; 64.8% voted in favor of Proposition 8 which amended California Constitution to prohibit same-sex marriages.