New Castle is a town in Rockingham County, New Hampshire, United States. The population was 968 at the 2010 census. It is the smallest and easternmost town in New Hampshire, and the only one located entirely on islands. It is home to Fort Constitution Historic Site, Fort Stark Historic Site, and the New Castle Common, a 31-acre (13 ha) recreation area on the Atlantic Ocean. New Castle is also home to a United States Coast Guard station, as well as the historic Wentworth by the Sea hotel.
According to the United States Census Bureau, the town has a total area of 2.4 square miles (6.2 km), of which 0.8 sq mi (2.1 km) is land and 1.5 sq mi (3.9 km) is water, comprising 65.13% of the town. New Castle occupies an archipelago, consisting of one main island (Great Island) and several smaller islands surrounded by the Piscataqua River and Atlantic Ocean. The highest point of land is located at The Wentworth-by-the-Sea Hotel, where the elevation reaches 60 feet (18 m) above sea level.
As of the census of 2000, there were 1,010 people, 443 households, and 314 families residing in the town. The population density was 1,222.6 people per square mile (469.8/km). There were 488 housing units at an average density of 590.7 per square mile (227.0/km). The racial makeup of the town was 97.82% White, 0.59% African American, 0.50% Asian, and 1.09% from two or more races. Hispanic or Latino of any race were 0.50% of the population.
There were 443 households out of which 22.1% had children under the age of 18 living with them, 61.6% were married couples living together, 5.0% had a female householder with no husband present, and 29.1% were non-families. 23.9% of all households were made up of individuals and 11.5% had someone living alone who was 65 years of age or older. The average household size was 2.26 and the average family size was 2.65.
In the town, the population was spread out with 17.8% under the age of 18, 3.4% from 18 to 24, 20.8% from 25 to 44, 34.0% from 45 to 64, and 24.1% who were 65 years of age or older. The median age was 50 years. For every 100 females, there were 95.7 males. For every 100 females age 18 and over, there were 97.1 males.
The median income for a household in the town was $83,708, and the median income for a family was $93,290. Males had a median income of $57,375 versus $35,568 for females. The per capita income for the town was $67,695. None of the families and 0.6% of the population were living below the poverty line, including no under 18 and none of those over 65. New Castle was New Hampshire’s wealthiest town in terms of median per capita income.