Moreno Valley is a city located in Riverside County, California. As of January 1, 2008, the population of Moreno Valley was 180,466. A relatively young city, its rapid growth in the 1980s and the 2000s propelled it to its status as second-largest city in Riverside County by population, and one of the Inland Empire's population centers. Neighboring Riverside, California is the county seat and largest city in the county; the two cities are closely tied, sharing March Air Reserve Base, among other things.