Bannerman's Castle is a historic structure located on Pollepel Island in the Hudson River, New York. Built in the early 1900s by Francis Bannerman VI, a Scottish-American arms dealer, the castle was originally intended as a storage facility for his military surplus business. The castle features a unique blend of Scottish baronial architecture and military design. The site is now a popular destination for tourists and history enthusiasts. It is accessible by boat, and guided tours are offered to explore the ruins and learn about the castle's history, as well as the surrounding natural beauty of the Hudson River and Hudson Highlands.