The population count of Maricopa County, AZ was 4,253,913 in 2018. The population count of Riverside County, CA was 2,383,286 in 2018. The population count of Bernalillo County, NM was 677,692 in 2018.
Population
Population Change
Above charts are based on data from the U.S. Census American Community Survey | ODN Dataset | API -