The town was first named Stonington in 1761, probably due to Governor Benning Wentworth's shipbuilding interests in Stonington, Connecticut. It was renamed Northumberland in honor of Hugh Smithson, first Duke of Northumberland. The Duke's son, James Smithson, is remembered for leaving a legacy of more than a half million dollars for the founding of the Smithsonian Institution. Most of Northumberland's residents live in the village of Groveton.
