Seabrook is a town in Rockingham County, New Hampshire, United States. The population was 8,693 at the 2010 census. Located at the southern end of the coast of New Hampshire on the border with Massachusetts, Seabrook is noted as the location of the Seabrook Nuclear Power Station, the third-most recently constructed nuclear power plant in the United States.
According to the United States Census Bureau, the town has a total area of 9.6 square miles (25 km2), of which 8.9 sq mi (23 km2) is land and 0.8 sq mi (2.1 km2) is water, comprising 7.8% of the town. The census-designated place of Seabrook Beach occupies the eastern end of the town, along the Atlantic Ocean. The highest point in Seabrook is 217 feet (66 m) above sea level on Grape Hill, whose 230-foot (70 m) summit lies just south of the town line in Salisbury, Massachusetts.
As of the 2010 census, there were 8,693 people, 3,706 households and 2,276 families living in the town. The population density was 977 per square mile (380/km2). There were 4,544 housing units in the town, 838 of which (18.4%) were vacant. 512 of the vacant units were for seasonal or recreational use.