Auburn is located in Sangamon county Illinois with a geographic area of 4.1 square miles. The total population in Auburn is 4,701 with 49.2% male and 50.8% female. Children under age 5 represent 5.8% of the population, under age 18 equal 24.8% of the population and over age 65 is 14.4% of the population. The median household income is $71,537, per capita income is $31,083. There are a total of 1,683 housing units with 87.4% owner occupied. Education includes 34.8% of residents that are high school graduates and 22.1% with a bachelor's degree or higher. The average temperature in Auburn in the summer is 75 degrees, and in the winter 27 degrees.