Manchester is a city in St. Louis County, Missouri, United States. The population was 19,161 at the 2000 census. The mayor is David Willson.
Manchester is located at 38°35′3″N 90°30′27″W / 38.58417°N 90.5075°W / 38.58417; -90.5075 (38.584244, -90.507449).
According to the United States Census Bureau, the city has a total area of 5.0 square miles (12.9 km²), all of it land.