West Peoria is a city in Peoria County, Illinois, United States. The population was 4,458 at the 2010 census. West Peoria is a suburb o…West Peoria is a city in Peoria County, Illinois, United States. The population was 4,458 at the 2010 census. West Peoria is a suburb of Peoria and is part of the Peoria, Illinois Metropolitan Statistical Area.