Effingham is located in Effingham county Illinois with a geographic area of 10.3 square miles. The total population in Effingham is 12,310 with 46.6% male and 53.4% female. Children under age 5 represent 7.1% of the population, under age 18 equal 22.9% of the population and over age 65 is 19.2% of the population. The median household income is $52,551, per capita income is $31,029. There are a total of 5,205 housing units with 62.2% owner occupied. Education includes 33.5% of residents that are high school graduates and 17.8% with a bachelor's degree or higher. The average temperature in Effingham in the summer is 74 degrees, and in the winter 27 degrees.