The northern half of the town drains into Lake Sunapee, which in turns drains west via the Sugar River into the Connecticut River and thence to Long Island Sound. The southern half of the town, including the eastern side of Mount Sunapee, drains via Andrew Brook and the West Branch of the Warner River to the Warner River, which flows east to the Contoocook River, then into the Merrimack River, and ultimately to the Gulf of Maine.