Boldt Castle
Boldt Castle is a castle on Heart Island in the St. Lawrence River, built by George C. Boldt from 1900 and owned and operated by the Thousand Islands Bridge Authority. The site includes the castle, gardens and grounds, the Yacht House and the Alster Tower.
Details
| Address | Heart Island, Alexandria Bay, NY 13607 (office: PO Box 428, Collins Landing, Alexandria Bay, NY 13607) |
|---|---|
| Phone | 315-482-9724 |
| Website | boldtcastle.com |
| Season | Opens early May (May 8 for the 2027 season) |
| Category | Attraction |
| Location | Town of Alexandria, United States (44.34455, -75.92244 on OpenStreetMap) |
| Nearest island or place | Heart Island |
Sources: boldtcastle.com; openstreetmap.org; coordinates: © OpenStreetMap contributors (ODbL). Last checked 2026-10-21.