Lincoln is located in Middlesex county Massachusetts with a geographic area of square miles. The total population in Lincoln is 6,868 with 52.7% male and 47.3% female. Children under age 5 represent 7.5% of the population, under age 18 equal 28.0% of the population and over age 65 is 19.4% of the population. The median household income is $140,888, per capita income is $86,719. There are a total of 2,569 housing units with 61.0% owner occupied. Education includes 5.8% of residents that are high school graduates and 74.7% with a bachelor's degree or higher. The average temperature in Lincoln in the summer is 70 degrees, and in the winter 30 degrees.