Moreno Valley is a city in Riverside County, California, United States, and is part of the Riverside–San Bernardino–Ontario metropolitan area. I…Moreno Valley is a city in Riverside County, California, United States, and is part of the Riverside–San Bernardino–Ontario metropolitan area. It is the second-largest city in Riverside County by population and one of the Inland Empire's population centers. The city's population was 208,634 at the 2020 census. Moreno Valley is also part of the greater Los Angeles area.