Cortland is located in Dekalb county Illinois with a geographic area of 3.6 square miles. The total population in Cortland is 4,261 with 54.7% male and 45.3% female. Children under age 5 represent 9.1% of the population, under age 18 equal 26.0% of the population and over age 65 is 7.9% of the population. The median household income is $74,821, per capita income is $32,578. There are a total of 1,419 housing units with 73.6% owner occupied. Education includes 23.3% of residents that are high school graduates and 33.8% with a bachelor's degree or higher. The average temperature in Cortland in the summer is 74 degrees, and in the winter 27 degrees.
