The town was granted in 1735 as "Number One" by Massachusetts Governor Jonathan Belcher to petitioners largely from Amesbury, Massachusetts. Called "New Amesbury", it was part of a line of settlements running between the Merrimack and Connecticut rivers intended to help defend Massachusetts against New France's predations. It was regranted by the Masonian Proprietors in 1749, when it was settled with four houses and a sawmill. Called "Jennesstown", it was abandoned and destroyed during the French and Indian War. The town was granted again in 1767 to Jonathan Barnard and others, who called it "Amesbury". But on September 3, 1774, it was incorporated as "Warner", named after Jonathan Warner, a leading Portsmouth citizen, namesake of the Warner House and relative of Governor John Wentworth. It was one of the last towns established under English provincial rule prior to the Revolution.