Crystal lake is located in Mchenry county Illinois with a geographic area of 18.9 square miles. The total population in Crystal lake is 39,685 with 50.3% male and 49.7% female. Children under age 5 represent 5.3% of the population, under age 18 equal 24.4% of the population and over age 65 is 15.4% of the population. The median household income is $91,456, per capita income is $39,782. There are a total of 14,393 housing units with 75.9% owner occupied. Education includes 20.5% of residents that are high school graduates and 41.2% with a bachelor's degree or higher. The average temperature in Crystal lake in the summer is 74 degrees, and in the winter 27 degrees.
