Boldt Castle is a popular landmark and tourist destination in New York’s Thousand Islands region. Open to visitors from mid-May to mid-October, it’s situated on Heart Island in the Saint Lawrence River, which is part of the Town of Alexandria in Jefferson County. Originally built as a private mansion by millionaire George Boldt, the castle is now managed by the Thousand Islands Bridge Authority as a tourist site. You can find photos on Boldt Castle’s Facebook, Instagram, website, and Wikipedia.
At the turn of the 20th century, millionaire George C. Boldt, owner of the famous Waldorf Astoria Hotel in New York City, began building a grand Rhineland-style castle on Heart Island in Alexandria Bay as a symbol of his love for his wife, Louise.
Construction started in 1900, with the Boldt family spending their summers at their Wellesley House near Wellesley Island Farms while a team of 300 workers, including stonemasons, carpenters, and artists, worked on the six-story, 120-room castle. It was designed to include tunnels, a powerhouse, Italian gardens, a drawbridge, Alster Tower (a playhouse for children), and a dove cote—no detail or expense was spared.
Sadly, in January 1904, tragedy struck when Louise suddenly passed away. Heartbroken, George Boldt halted all construction on the castle, unable to continue without his beloved. He never returned, leaving the castle as a lasting monument of his love for Louise.
For 73 years, the castle and other structures were left to weather the elements and vandalism. In 1977, the Thousand Islands Bridge Authority took ownership and decided to preserve the property using the proceeds from the castle’s operations. Since then, millions of dollars have been invested in restoring and improving the structures on Heart Island.
Today, Boldt Castle is open to the public and can be accessed by ferry, private boat, or tour boat from Alexandria Bay, Clayton (New York), and Gananoque, Rockport, and Ivy Lea (Ontario). Most of the grounds and buildings are open for exploration with an admission fee. Visitors arriving by boat can dock at Heart Island for free. There’s also a U.S. Customs and Border Protection office on the island for those arriving from Canada, as visiting the island counts as entering the United States.
As of 2011, most of the first-floor rooms and several on the second floor of Boldt Castle have been furnished, though with mostly modern pieces. The basement remains largely unfinished, featuring a pool, bowling lanes, various rooms, and a long passageway leading to the Power House. While many of the rooms from the second to the top floor are unfurnished, some have exhibits showcasing photos and artifacts from the Thousand Islands region during the Boldt family’s time. These unfurnished rooms allow visitors to imagine how the castle looked before its modern updates.
At the island’s edge, a stone triumphal arch, originally meant by George Boldt to be the main entrance for boats, has been fully restored. The bridge connecting both sides would have been raised and lowered as needed.
Two other buildings on Heart Island, the Power House and the Alster Tower, are also open to the public. The Power House was originally built to house a generator that provided electricity to the island. Today, it serves as a museum, showcasing how power was generated in the early 1900s and sharing stories about how tools and equipment were transported to the island during the castle’s construction. The Alster Tower, on the other hand, was intentionally designed with slanted, uneven walls, ceilings, and roofs, giving it a quirky and unique character.
The George C. Boldt Yacht House, located on nearby Wellesley Island, is a unique attraction worth visiting. A shuttle boat connects it to Heart Island, making it easy for visitors to explore both. The Yacht House was added to the National Register of Historic Places in 1978, highlighting its historical significance.
