Clayton is a city in and the county seat of St. Louis County, Missouri, United States, and borders the city of St. Louis. The population was 15,939 at the 2010 census. The city was organized in 1877 and is named after Ralph Clayton, who donated the land for the courthouse.
According to the United States Census Bureau, the city has a total area of 2.48 square miles (6.42 km), all land.
In the St. Louis region, Clayton is well known for housing a wealthy and educated young professional, often dual-income population.
As of the census of 2010, there were 15,939 people, 5,322 households, and 2,921 families residing in the city. The population density was 6,427.0 inhabitants per square mile (2,481.5/km). There were 6,321 housing units at an average density of 2,548.8 per square mile (984.1/km). The racial makeup of the city was 78.0% White, 8.2% African American, 0.2% Native American, 10.8% Asian, 0.4% from other races, and 2.4% from two or more races. Hispanic or Latino of any race were 3.1% of the population.
There were 5,322 households of which 26.3% had children under the age of 18 living with them, 46.3% were married couples living together, 6.7% had a female householder with no husband present, 1.9% had a male householder with no wife present, and 45.1% were non-families. 37.5% of all households were made up of individuals and 11.2% had someone living alone who was 65 years of age or older. The average household size was 2.12 and the average family size was 2.86.
The median age in the city was 29.2 years. 15.8% of residents were under the age of 18; 27.6% were between the ages of 18 and 24; 23.3% were from 25 to 44; 21.6% were from 45 to 64; and 11.8% were 65 years of age or older. The gender makeup of the city was 50.9% male and 49.1% female.
In 2012, the median income per household was $87,756, up from $64,184 in 2010.
As of the census of 2000, there were 12,825 people, 5,370 households, and 2,797 families residing in the city. The population density was 5,164.4 people per square mile (1,996.7/km²). There were 5,852 housing units at an average density of 2,356.5 per square mile (911.1/km²). The racial makeup of the city was 84.94% White, 7.77% Black or African American, 0.12% Native American, 5.62% Asian, 0.03% Pacific Islander, 0.29% from other races, and 1.22% from two or more races. Hispanic or Latino of any race were 1.49% of the population.
There were 5,370 households out of which 25.9% had children under the age of 18 living with them, 43.4% were married couples living together, 6.7% had a female householder with no husband present, and 47.9% were non-families. 40.4% of all households were made up of individuals and 11.8% had someone living alone who was 65 years of age or older. The average household size was 2.09 and the average family size was 2.90.
In the city, the population was spread out with 20.1% under the age of 18, 10.7% from 18 to 24, 32.3% from 25 to 44, 22.6% from 45 to 64, and 14.3% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 100.5 males. For every 100 females age 18 and over, there were 98.0 males.
The median income for a household in the city was $64,184, and the median income for a family was $107,346. Males had a median income of $64,737 versus $42,757 for females. The per capita income for the city was $48,055. About 5.0% of families and 7.7% of the population were below the poverty line, including 9.5% of those under age 18 and 3.2% of those age 65 or over.