Valcour Island is an 895-acre island in Lake Champlain in Clinton County, New York, USA. The island is mostly in the Town of Peru and partly in the Town of Plattsburgh, southeast of the City of Plattsburgh.

Valcour Island, about two miles (3 km) long and a mile (2 km) broad, lies by the western shore of Lake Champlain, forming a narrow strait against the New York mainland. Its shores are alternately rocky, craggy outcroppings and sandy beaches. Several protected bays provide anchorages. The Bluff Point Light stands on the western shore. It guided boats through the narrow strait from 1871 until 1930 when it was replaced by a steel tower.