Riverside County is a county

County (United States)

In the United States, a county is a geographic subdivision of a state , usually assigned some governmental authority. The term "county" is used in 48 of the 50 states; Louisiana is divided into parishes and Alaska into boroughs. Parishes and boroughs are called "county-equivalents" by the U.S...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. One of 58 California counties, it covers 7208 sq mi (18,669 km²) in the southern part of the state, and stretches from Orange County

Orange County, California

Orange County is a county in the U.S. state of California. Its county seat is Santa Ana. As of the 2010 census, its population was 3,010,232, up from 2,846,293 at the 2000 census, making it the third most populous county in California, behind Los Angeles County and San Diego County...

 to the Colorado River, which forms the state border with Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

. The county derives its name from the city of Riverside

Riverside, California

Riverside is a city in Riverside County, California, United States, and the county seat of the eponymous county. Named for its location beside the Santa Ana River, it is the largest city in the Riverside-San Bernardino-Ontario metropolitan area of Southern California, 4th largest inland California...

, which is the county seat

County seat

A county seat is an administrative center, or seat of government, for a county or civil parish. The term is primarily used in the United States....

. Along with neighboring San Bernardino County

San Bernardino County, California

San Bernardino County is a county in the U.S. state of California. As of the 2010 census, the population was 2,035,210, up from 1,709,434 as of the 2000 census...

, the two counties have been dubbed the 'Inland Empire

Inland Empire (California)

The Inland Empire is a region in Southern California. The region sits directly east of the Los Angeles metropolitan area. The Inland Empire most commonly is used in reference to the U.S. Census Bureau's federally-defined Riverside-San Bernardino-Ontario metropolitan area, which covers more than...

'.

The population of Riverside County was 2,189,641 in 2010.

Geographically, the county is mostly desert

Desert

A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...

 in the central and eastern portions of the county, and is a Mediterranean climate

Mediterranean climate

A Mediterranean climate is the climate typical of most of the lands in the Mediterranean Basin, and is a particular variety of subtropical climate...

 in the western portion of the county.