Harrisville is a town in Cheshire County, New Hampshire, United States. Besides the town center, it also includes the village of Chesham. The population of the town was 961 at the 2010 census.
According to the United States Census Bureau, the town has a total area of 20.2 square miles (52 km), of which 18.6 square miles (48 km) is land and 1.6 square miles (4.1 km) is water, comprising 7.80% of the town. The highest point in Harrisville is the summit of Cobb Hill, at 1,909 feet (582 m) above sea level. Roughly the western half of Harrisville, drained by Minnewawa Brook, lies within the Ashuelot River watershed, part of the Connecticut River basin, while the eastern half, drained by Nubanusit Brook, is in the Merrimack River watershed. Significant lakes include Silver Lake, Seaver Reservoir, and Chesham Pond on the western side, and Harrisville Pond and Skatutakee Lake draining to the east.
As of the census of 2000, there were 1,075 people, 449 households, and 306 families residing in the town. The population density was 57.4 people per square mile (22.1/km²). There were 698 housing units at an average density of 37.2 per square mile (14.4/km²). The racial makeup of the town was 97.77% White, 0.09% African American, 0.56% Native American, 0.28% Asian, and 1.30% from two or more races. Hispanic or Latino of any race were 0.56% of the population.
There were 449 households out of which 31.2% had children under the age of 18 living with them, 55.2% were married couples living together, 8.9% had a female householder with no husband present, and 31.8% were non-families. 26.5% of all households were made up of individuals and 7.8% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 2.87.
In the town, the population was spread out with 24.8% under the age of 18, 4.6% from 18 to 24, 25.7% from 25 to 44, 30.0% from 45 to 64, and 15.0% who were 65 years of age or older. The median age was 43 years. For every 100 females, there were 92.3 males. For every 100 females age 18 and over, there were 87.0 males.
The median income for a household in the town was $48,625, and the median income for a family was $55,083. Males had a median income of $34,625 versus $27,171 for females. The per capita income for the town was $25,397. About 4.3% of families and 5.7% of the population were below the poverty line, including 8.0% of those under age 18 and 3.8% of those age 65 or over.