Middlesex is located in Middlesex county New jersey with a geographic area of 3.5 square miles. The total population in Middlesex is 13,606 with 47.5% male and 52.5% female. Children under age 5 represent 4.5% of the population, under age 18 equal 22.0% of the population and over age 65 is 14.8% of the population. The median household income is $84,216, per capita income is $38,136. There are a total of 4,909 housing units with 74.6% owner occupied. Education includes 29.9% of residents that are high school graduates and 30.1% with a bachelor's degree or higher. The average temperature in Middlesex in the summer is 73 degrees, and in the winter 34 degrees.