Amherst is a town in Hillsborough County, New Hampshire, United States. The population was 11,201 at the 2010 census. Amherst is home to Ponemah Bog Wildlife Sanctuary, Hodgman State Forest, the Joe English Reservation and Baboosic Lake.
According to the United States Census Bureau, the town has a total area of 34.8 square miles (90 km2), of which 34.3 square miles (89 km2) is land and 0.5 square miles (1.3 km2) is water, comprising 1.49% of the town. Located on the Souhegan River, Amherst is drained by Beaver, Bloody, and Joe English brooks. Amherst's highest point is on Chestnut Hill at the town's northern border, where the elevation reaches 865 feet (264 m) above sea level. Amherst lies fully within the Merrimack River watershed.
AAs of the census of 2000, there were 10,769 people, 3,590 households, and 3,065 families residing in the town. The population density was 314.1 people per square mile (121.3/kmē). There were 3,752 housing units at an average density of 109.4 per square mile (42.2/kmē).