Middlefield is located in Middlesex county Connecticut with a geographic area of square miles. The total population in Middlefield is 4,375 with 48.8% male and 51.2% female. Children under age 5 represent 3.4% of the population, under age 18 equal 17.0% of the population and over age 65 is 22.0% of the population. The median household income is $79,042, per capita income is $44,539. There are a total of 1,842 housing units with 80.6% owner occupied. Education includes 35.3% of residents that are high school graduates and 32.2% with a bachelor's degree or higher. The average temperature in Middlefield in the summer is 68 degrees, and in the winter 27 degrees.