Croydon is a town in Sullivan County, New Hampshire, United States. The population was 764 at the 2010 census.
According to the United States Census Bureau, the town has a total area of 37.5 square miles (97.1 km), of which 36.7 square miles (95.1 km) is land and 0.8 square miles (2.1 km) is water, comprising 2.06% of the town. The highest point in town is Croydon Peak, at 2,760 feet (840 m) above sea level. Croydon lies fully within the Connecticut River watershed.
Croydon is home to Corbin Park, one of the largest private game reserves in New England. The 24,000-acre (9,700 ha) fenced-in expanse of woodlands and mountainous terrain features bison, European boar and elk and extends into neighboring towns.
As of the census of 2000, there were 661 people, 264 households, and 194 families residing in the town. The population density was 17.8 people per square mile (6.9/km²). There were 354 housing units at an average density of 9.5 per square mile (3.7/km²). The racial makeup of the town was 97.43% White, 0.45% Native American, 0.15% Asian, 0.76% from other races, and 1.21% from two or more races. Hispanic or Latino of any race were 0.61% of the population.
There were 264 households out of which 29.2% had children under the age of 18 living with them, 58.0% were married couples living together, 8.3% had a female householder with no husband present, and 26.5% were non-families. 19.3% of all households were made up of individuals and 8.7% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 2.71.
In the town, the population was spread out with 22.7% under the age of 18, 4.7% from 18 to 24, 30.4% from 25 to 44, 30.0% from 45 to 64, and 12.3% who were 65 years of age or older. The median age was 41 years. For every 100 females, there were 109.2 males. For every 100 females age 18 and over, there were 102.0 males.
The median income for a household in the town was $49,688, and the median income for a family was $50,556. Males had a median income of $31,992 versus $26,544 for females. The per capita income for the town was $21,403. About 2.5% of families and 4.9% of the population were below the poverty line, including 5.0% of those under age 18 and 9.7% of those age 65 or over.