Grantham is located in Sullivan county New hampshire with a geographic area of square miles. The total population in Grantham is 2,948 with 46.9% male and 53.1% female. Children under age 5 represent 0.0% of the population, under age 18 equal 21.0% of the population and over age 65 is 23.0% of the population. The median household income is $126,302, per capita income is $50,414. There are a total of 1,183 housing units with 89.5% owner occupied. Education includes 7.4% of residents that are high school graduates and 73.9% with a bachelor's degree or higher. The average temperature in Grantham in the summer is 68 degrees, and in the winter 23 degrees.
