Which fort was attacked in the Battle of the Thousand Islands in 1760?

The fort attacked in the 1760 Battle of the Thousand Islands was Fort Lévis.

The French built Fort Lévis in 1759 on Isle Royale, an island in the St. Lawrence River near present-day Ogdensburg, New York. Its position near rapids made it a useful defensive point: attacking vessels had to approach through constricted waters, while guns on the island could challenge ships moving upstream.

In August 1760, British commander Jeffery Amherst advanced from Oswego with a much larger force as part of the campaign to conquer Montreal. The battle lasted from August 16 to 24. A small French garrison resisted bombardment and naval attacks, sinking two British vessels and damaging another before ammunition ran short. The fort then surrendered.

Fort Lévis is often confused with Fort Frontenac or Fort Niagara, both important French strongholds in the same theater. Fort Niagara had already fallen to the British in 1759, while Fort Lévis was the specific position attacked in the Thousand Islands engagement. The British renamed it Fort William Augustus; its remains were later submerged during construction of the St. Lawrence Seaway.