Alton is located in Madison county Illinois with a geographic area of 15.7 square miles. The total population in Alton is 26,490 with 47.9% male and 52.1% female. Children under age 5 represent 5.9% of the population, under age 18 equal 24.3% of the population and over age 65 is 16.6% of the population. The median household income is $43,291, per capita income is $24,943. There are a total of 11,325 housing units with 60.0% owner occupied. Education includes 26.6% of residents that are high school graduates and 19.4% with a bachelor's degree or higher. The average temperature in Alton in the summer is 76 degrees, and in the winter 27 degrees.
