High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Saint Peters is a city in St. Charles County, Missouri, United States. The official population estimate was 55,500 as of 2008. Interstate 70 passes through the city, providing a major transportation link. In 2008 St. Peters was dubbed the 60th best place to live by Money magazine, putting it at the top in the state of Missouri. The "Rec-Plex" in St. Peters is an award-winning recreation and fitness complex that underwent an $18.5 million expansion in 2007. The city also hosts the county's largest shopping center, Mid Rivers Mall, which plans a 120,000 sq ft (11,000 m2) expansion.