Caseyville is located in St. clair county Illinois with a geographic area of 7.3 square miles. The total population in Caseyville is 4,203 with 54.4% male and 45.6% female. Children under age 5 represent 7.7% of the population, under age 18 equal 26.4% of the population and over age 65 is 17.2% of the population. The median household income is $51,610, per capita income is $22,927. There are a total of 1,437 housing units with 71.2% owner occupied. Education includes 32.2% of residents that are high school graduates and 17.0% with a bachelor's degree or higher. The average temperature in Caseyville in the summer is 74 degrees, and in the winter 27 degrees.