Île-aux-Noix (ēl-ō-nwä) [key], island, 210 acres (85 hectares), in the Richelieu River near St. Jean, S Que., Canada; site of Fort Lennox National Historic Park (est. 1921). During the French and Indian War (1759) the French built a fort there to delay the British advance on Montreal but were forced to surrender it in 1760. Named Fort Lennox and occupied by a British garrison, the island fell (1775) to American forces and was used as a base by the American generals Schuyler and Montgomery for attacks on Montreal and Quebec until abandoned in 1776. The British then used the island to supply their operations against the American fleet on Lake Champlain. The present Fort Lennox dates from the 1820s, when the old fortifications were repaired and additions were built. It was a military post until 1870.