Anna is located in Union county Illinois with a geographic area of 3.6 square miles. The total population in Anna is 4,149 with 52.5% male and 47.5% female. Children under age 5 represent 6.2% of the population, under age 18 equal 21.6% of the population and over age 65 is 22.8% of the population. The median household income is $36,303, per capita income is $22,455. There are a total of 1,699 housing units with 68.9% owner occupied. Education includes 27.4% of residents that are high school graduates and 20.4% with a bachelor's degree or higher. The average temperature in Anna in the summer is 76 degrees, and in the winter 27 degrees.