is a large city located in the Inland Empire in Southern California. It is also the county seat of Riverside County, California, United States. The city is named for the nearby Santa Ana River, and is the birthplace of the California citrus industry. As of 2008, Riverside has an estimated population of 311,575. Riverside is the 61st-largest city in the United States, 12th largest city in California, the largest city in California's Inland Empire region, the fourth largest inland city in California, the 14th-largest metropolitan area in the nation and part of the 2nd largest Combined Statistical Area in the country. The city anticipates that the population of Riverside will surpass 320,000 by 2010. Riverside is one of the fastest growing cities in the U.S. Riverside is also one of the best places to live according to Money Magazine.
Compared with other cities in Southern California, real estate prices in Riverside are significantly lower than those in adjacent counties. This has led to steady growth in Riverside. Consequently, this has also contributed to heavy traffic as residents from Riverside commute to job centers in Orange County and Los Angeles.
In the 2000s, Riverside has been listed by various research groups as having some of the United States' most severe air pollution and congestion. Smart Growth America lists Riverside as the most sprawling city in the nation. However, according to the United States Bureau of the Census, the corresponding Riverside-San Bernardino urbanized area had a population density of 3,400 per square mile in 2000, slightly above that of Portland, Oregon, which is often cited as an example of having contained urban sprawl (suburbanization).
According to the United States Census Bureau, the city has a total area of , of which, 98.1 square miles (222.3 km²) of it is land and 0.3 square miles (0.7 km²) of it is water. The total area is 0.36% water. Downtown Riverside sits on an elevation of 860 feet. There are some hills in the city limits of Riverside. Riverside is surrounded by small and large mountains, some of which get snow during the colder months of the year.