Heart Island

This article is about the island on the Saint Lawrence River. For the island in Long Island Sound, see Hart Island (Bronx).

Not to be confused with Hart Island (disambiguation).

Panoramic view of Heart Island and Boldt Castle in the Thousand Islands of Upstate New York

Heart Island is an island in the Town of Alexandria, Jefferson County, New York, within the Saint Lawrence River, along the Canada–United States border. The island is one of the most prominent within the Thousand Islands archipelago of the two countries.

Heart Island is home to Boldt Castle, which is open to the public as a tourist attraction.