Carleton Island is located in the St Lawrence River in upstate New York. It is part of the Town of Cape Vincent, in Jefferson County. It was the location of Fort Haldimand, controlled by the British during the American Revolution, and of great strategic importance, as well as being a center of shipbuilding. The ruins of the fort can still be seen at the southwest end of the island. Projecting from the location of the fort is Government Point, notched by two small bays. Houses on the island used to be serviced by a ferry running from the island to the village of Cape Vincent, but it is no longer in service. Today many of the residents use their own recreational craft to travel to and from the island. One resident even owns an air boat so he can get to his house in the winter over the ice.[c