Northfield is located in Cook county Illinois with a geographic area of 3.2 square miles. The total population in Northfield is 5,678 with 46.1% male and 53.9% female. Children under age 5 represent 4.2% of the population, under age 18 equal 18.8% of the population and over age 65 is 28.3% of the population. The median household income is $143,661, per capita income is $103,893. There are a total of 2,407 housing units with 90.8% owner occupied. Education includes 4.7% of residents that are high school graduates and 77.6% with a bachelor's degree or higher. The average temperature in Northfield in the summer is 74 degrees, and in the winter 27 degrees.
