Riverside is a city in and the county seat of Riverside County, California, United States, in the Inland Empire metropolitan area. It is named for its location beside the Santa Ana River. It is the most populous city in the Inland Empire and in Riverside County, and is about 50 miles southeast of downtown Los Angeles. It is also part of the Greater Los Angeles area. Riverside is the 59th-most-populous city in the United States and the 12th-most-populous city in California.