Riverside, the county seat of Riverside County, California, is located in the Inland Empire metropolitan area. It is named for its proximity to the Santa Ana River. With a population of 317,261, Riverside is the twelfth most populous city in California among 1578 cities. Irvine and Santa Ana are close behind with 309,031 and 309,441 people respectively.
Riverside is the 61st most populous city in the United States and the twelfth most populous city in California. It is also home to several law, accounting, engineering and banking firms. The average age of Riverside's population is 31.1 years old. The population by age is 80,508 under 18 years old, 260,605 16 years or older, 250,861 18 years or older, 225,158 21 years or older and 42,908 65 years or older.
In the California State Legislature, the City of Riverside is in the 31st Senate District represented by Democrat Richard Roth. Riverside Municipal Airport is an airport within the city limits of Riverside but it has no commercial airline service. It is the 61st largest city in the United States and the twelfth largest city in California as well as the largest city in the Inland Empire metropolitan area of California.