Epsom is a town in Merrimack County, New Hampshire, United States. The population was 4,566 at the 2010 census.
According to the United States Census Bureau, the town has a total area of 34.4 square miles (89 km), of which 34.2 sq mi (89 km) is land and 0.2 sq mi (52 ha) is water, comprising 0.58% of the town. The highest point in Epsom is the summit of Fort Mountain, at 1,413 feet (431 m) above sea level, in the eastern part of town. Other neighboring small mountains in town include McCoy Mountain (1,270 ft or 390 m) and Nats Mountain (1,180 ft or 360 m). The town is drained by the Suncook River. Epsom lies fully within the Merrimack River watershed.
As of the census of 2000, there were 4,021 people, 1,491 households, and 1,103 families residing in the town. The population density was 117.7 people per square mile (45.4/km²). There were 1,592 housing units at an average density of 46.6 per square mile (18.0/km²). The racial makeup of the town was 98.63% White, 0.10% African American, 0.10% Native American, 0.32% Asian, 0.10% from other races, and 0.75% from two or more races. Hispanic or Latino of any race were 0.45% of the population.
There were 1,491 households out of which 34.2% had children under the age of 18 living with them, 64.0% were married couples living together, 6.9% had a female householder with no husband present, and 26.0% were non-families. 19.7% of all households were made up of individuals and 7.4% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.01.
In the town, the population was spread out with 24.5% under the age of 18, 5.3% from 18 to 24, 30.9% from 25 to 44, 25.4% from 45 to 64, and 14.0% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 92.1 males. For every 100 females age 18 and over, there were 89.8 males.
The median income for a household in the town was $50,685, and the median income for a family was $56,875. Males had a median income of $40,995 versus $27,106 for females. The per capita income for the town was $22,026. About 1.9% of families and 3.1% of the population were below the poverty line, including 3.4% of those under age 18 and 3.2% of those age 65 or over.