Dennis is located in Barnstable county Massachusetts with a geographic area of 4.9 square miles. The total population in Dennis is 1,962 with 48.1% male and 51.9% female. Children under age 5 represent 1.3% of the population, under age 18 equal 4.9% of the population and over age 65 is 50.4% of the population. The median household income is $93,726, per capita income is $61,161. There are a total of 1,031 housing units with 83.4% owner occupied. Education includes 16.6% of residents that are high school graduates and 61.7% with a bachelor's degree or higher. The average temperature in Dennis in the summer is 70 degrees, and in the winter 30 degrees.