Ballwin is a second-ring western suburb of St. Louis, located in St. Louis County, Missouri, United States. The population was 30,264 as of 2006. It was named by Money Magazine in 2005 as 64th on the list of the 100 best cities in America. It is the only city in America named Ballwin.
According to the United States Census Bureau, the city has a total area of 8.9 square miles (23.2 km²), all of it land.
As of the census of 2000, there were 31,283 people, 11,797 households, and 8,942 families residing in the city. The population density was 3,494.6 people per square mile (1,349.5/km²). There were 12,062 housing units at an average density of 1,347.4/sq mi (520.4/km²). The racial makeup of the city was 93.39% White, 1.50% African American, 0.22% Native American, 3.27% Asian, 0.04% Pacific Islander, 0.51% from other races, and 1.07% from two or more races. Hispanic or Latino of any race were 1.86% of the population.
There were 11,797 households out of which 37.2% had children under the age of 18 living with them, 65.6% were married couples living together, 8.0% had a female householder with no husband present, and 24.2% were non-families. 20.6% of all households were made up of individuals and 7.3% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.09.
In the city the population was spread out with 27.0% under the age of 18, 6.4% from 18 to 24, 29.9% from 25 to 44, 24.5% from 45 to 64, and 12.1% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 94.2 males. For every 100 females age 18 and over, there were 91.6 males.
The median income for a household in the city was $66,458, and the median income for a family was $77,021. Males had a median income of $56,056 versus $32,202 for females. The per capita income for the city was $29,520. About 2.0% of families and 3.2% of the population were below the poverty line including 3.1% of those under age 18 and 3.7% of those age 65 or over.