Columbia is located in Monroe county Illinois with a geographic area of 10.3 square miles. The total population in Columbia is 10,692 with 49.4% male and 50.6% female. Children under age 5 represent 9.1% of the population, under age 18 equal 27.9% of the population and over age 65 is 14.0% of the population. The median household income is $107,500, per capita income is $50,876. There are a total of 4,068 housing units with 86.1% owner occupied. Education includes 13.7% of residents that are high school graduates and 54.2% with a bachelor's degree or higher. The average temperature in Columbia in the summer is 76 degrees, and in the winter 27 degrees.
