Colchester is located in Hancock county Illinois with a geographic area of 1.2 square miles. The total population in Colchester is 1,347 with 51.8% male and 48.2% female. Children under age 5 represent 4.8% of the population, under age 18 equal 18.1% of the population and over age 65 is 19.0% of the population. The median household income is $43,942, per capita income is $24,095. There are a total of 569 housing units with 75.2% owner occupied. Education includes 35.9% of residents that are high school graduates and 25.1% with a bachelor's degree or higher. The average temperature in Colchester in the summer is 74 degrees, and in the winter 27 degrees.