Lempster is located in Sullivan county New hampshire with a geographic area of square miles. The total population in Lempster is 803 with 50.1% male and 49.9% female. Children under age 5 represent 6.1% of the population, under age 18 equal 19.7% of the population and over age 65 is 20.4% of the population. The median household income is $73,125, per capita income is $33,655. There are a total of 352 housing units with 92.0% owner occupied. Education includes 30.4% of residents that are high school graduates and 30.4% with a bachelor's degree or higher. The average temperature in Lempster in the summer is 68 degrees, and in the winter 23 degrees.