St. Peters is a city in St. Charles County, Missouri, United States. The population was 57,732 at the 2020 census, making it the eleventh-largest city in Missouri. It is a northwestern suburb of St. Louis. Interstate 70 passes through the city, providing a major transportation link. In 2008, St. Peters was named the 60th best place to live by Money magazine, putting it at the top in the state of Missouri. It also ranked in Money magazine's Top 100 in 2010, 2012 and 2017.