Valcour Bay is actually a strait or sound, located between Valcour Island and the west side of Lake Champlain, four miles south of Plattsburgh, New York. It was the site of the Battle of Valcour Island during the American Revolutionary War. It was declared a National Historic Landmark in 1961 because of this association. Valcour Bay is located in the Towns of Peru and Plattsburgh, both in Clinton County, New York.