Fort McClary is a former defensive fortification of the United States military located along the southern coast at Kittery Point, Maine at the mouth of the Piscataqua River. It was used throughout the 19th century to protect approaches to the harbor of Portsmouth, New Hampshire and the Portsmouth Naval Shipyard in Kittery. The property and its surviving structures are now owned and operated by the State of Maine as Fort McClary State Historic Site, including a blockhouse dating from 1844.