Manchester is a city in St. Louis County, Missouri, United States. The population was 18,094 at the 2010 census.
Manchester was named by an English settler after Manchester, England.
Manchester is located at 38°35′3″N 90°30′27″W (38.584244, -90.507449).
According to the United States Census Bureau, the city has a total area of 5.08 square miles (13.16 km2), all land.
As of the census of 2010, there were 18,094 people, 7,239 households, and 5,048 families living in the city. The population density was 3,561.8 inhabitants per square mile (1,375.2/km2). There were 7,553 housing units at an average density of 1,486.8 per square mile (574.1/km2). The racial makeup of the city was 87.6% White, 3.1% African American, 0.2% Native American, 6.0% Asian, 1.1% from other races, and 2.1% from two or more races. Hispanic or Latino of any race were 2.9% of the population.
There were 7,239 households of which 32.4% had children under the age of 18 living with them, 57.7% were married couples living together, 8.7% had a female householder with no husband present, 3.3% had a male householder with no wife present, and 30.3% were non-families. 24.3% of all households were made up of individuals and 7.7% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 3.00.