Cottleville is located in St. charles county Missouri with a geographic area of 4.6 square miles. The total population in Cottleville is 5,439 with 53.7% male and 46.3% female. Children under age 5 represent 6.5% of the population, under age 18 equal 25.4% of the population and over age 65 is 11.9% of the population. The median household income is $124,310, per capita income is $54,406. There are a total of 1,970 housing units with 85.0% owner occupied. Education includes 15.6% of residents that are high school graduates and 61.7% with a bachelor's degree or higher. The average temperature in Cottleville in the summer is 77 degrees, and in the winter 32 degrees.