Riverside County has a population of roughly 2,189,641 making it the fourth most populated county in California and the eleventh most populated in the United States. The county seat is the city of Riverside, which is where the county's name was derived from. Due to Riverside County's relatively affordable housing, large numbers of Los Angeles area workers have moved to the county in recent years. Riverside County is one of the fastest growing regions in the state prior to the recent changes in the regional economy.
The county is included in the Los Angeles-Long Beach Combined Statistical Area, as well as the Riverside-San Bernardino-Ontario Metropolitan Statistical Area which is also known as the Inland Empire. Roughly rectangular, Riverside County covers 7,208 square miles (18,670 km2) in Southern California, spanning from the greater Los Angeles area to the Arizona border. Geographically, the county is mostly desert in the central and eastern portions, but has a Mediterranean climate in the western portion. Most of Joshua Tree National Park is located in the county.
The indigenous peoples of what is now Riverside County are the Luiseño, Cupeño and Cahuilla Indians. The first European settlement in the county was a Mission San Luis Rey de Francia farm, at the Luiseño village of Temecula where grapes and grains were grown. In 1850 Riverside County was divided between San Diego County and Los Angeles County when the initial 27 California Counties were established. Riverside county has also been a focus of modern Native American Gaming enterprises.