Walpole is a town in Cheshire County, New Hampshire, United States. The population was 3,734 at the 2010 census.
According to the United States Census Bureau, the town has a total area of 36.7 square miles (95 km), of which 35.2 square miles (91 km) is land and 1.5 square miles (3.9 km) is water, comprising 4.16% of the town. The town is drained by the Connecticut River, which forms the western border of the town and is also the state border with Vermont. The northern part of Walpole is drained by the Cold River, a tributary of the Connecticut. The highest point in town is the summit of Derry Hill, at 1,663 feet (507 m) above sea level.
Walpole is served by state routes 12 and 123.
As of the census of 2010, there were 3,734 people, 1,576 households, and 1,036 families residing in the town. There were 1,715 housing units, of which 139, or 8.1%, were vacant. The racial makeup of the town was 97.3% white, 0.3% African American, 0.2% Native American, 0.5% Asian, 0.0% Native Hawaiian or Pacific Islander, 0.2% some other race, and 1.5% from two or more races. 1.3% of the population were Hispanic or Latino of any race.
Of the 1,576 households, 29.3% had children under the age of 18 living with them, 52.8% were headed by married couples living together, 8.9% had a female householder with no husband present, and 34.3% were non-families. 26.2% of all households were made up of individuals, and 12.2% were someone living alone who was 65 years of age or older. The average household size was 2.37, and the average family size was 2.86.
In the town, 21.8% of the population were under the age of 18, 6.2% were from 18 to 24, 22.9% from 25 to 44, 31.7% from 45 to 64, and 17.3% were 65 years of age or older. The median age was 44.5 years. For every 100 females, there were 95.2 males. For every 100 females age 18 and over, there were 92.0 males.
For the period 2011-2015, the estimated median annual income for a household was $66,613, and the median income for a family was $77,802. Male full-time workers had a median income of $49,141 versus $33,566 for females. The per capita income for the town was $35,071. 5.8% of the population and 4.8% of families were below the poverty line. 8.0% of the population under the age of 18 and 3.4% of those 65 or older were living in poverty.