The Battle of Valcour Island, also known as the Battle of Valcour Bay, was a naval engagement that took place on October 11, 1776, on Lake Champlain. The main action took place in Valcour Bay, a narrow strait between the New York mainland and Valcour Island. The battle is generally regarded as one of the first naval battles of the American Revolutionary War, and one of the first fought by the United States Navy. Most of the ships in the American fleet under the command of Benedict Arnold were captured or destroyed by a British force under the overall direction of General Guy Carleton. However, the American defense of Lake Champlain stalled British plans to reach the upper Hudson River valley.

Lake Champlain is a natural freshwater lake in North America. It mostly lies between the US states of New York and Vermont, but also extends north into the Canadian province of Quebec.