Jennings is a city in St. Louis County, Missouri, United States. The population was 14,712 at the 2010 census.GeographyJennings is located at .According to the United States Census Bureau, the city has a total area of 3.70sqmi, all land.Demographics2010 censusAs of the census of 2010, there were 14,712 people, 5,847 households, and 3,782 families residing in the city. The population density was 3976.2PD/sqmi. There were 6,937 housing units at an average density of 1874.9/sqmi. The racial makeup of the city was 89.8% African American, 8.5% White, 0.1% Native American, 0.2% Asian, 0.2% from other races, and 1.1% from two or more races. Hispanic or Latino of any race were 0.6% of the population.There were 5,847 households of which 36.4% had children under the age of 18 living with them, 22.4% were married couples living together, 36.0% had a female householder with no husband present, 6.3% had a male householder with no wife present, and 35.3% were non-families. 31.2% of all households were made up of individuals and 10.4% had someone living alone who was 65 years of age or older. The average household size was 2.51 and the average family size was 3.13.