Plattsburgh Bay, also known as Cumberland Bay, is an inlet on the western shore of Lake Champlain in Clinton County, New York. The bay is the location of the town and city of Plattsburgh, and was the site of the Battle of Plattsburgh, a naval and land engagement fought on September 11, 1814, late in the War of 1812. The bay and two land sites related to the battle were designated as a National Historic Landmark in 1960.