George Boldt halted construction in 1904, leaving 300 workmen idle and a six-storey Rhineland castle permanently unfinished on Heart Island.
His wife Louise had died suddenly in January; the 120-room monument to her—complete with powerhouse, Italian gardens, and a separate Alster Tower playhouse—would stand roofless and silent for seven decades. The Thousand Islands Bridge Authority acquired the property in 1977 and opened it to the public, investing all admission revenue into gradual restoration. Today the castle operates as a self-sustaining monument, its conservation fee funding masonry repair, interior furnishing, and seasonal scaffolding across the six-storey main structure.
Boldt Castle tours from Canada form the majority of summer visitation, with passengers departing Gananoque, Kingston, and Rockport aboard scheduled shuttle services that clear U.S. customs at the Heart Island dock. The castle occupies a 5.5-acre island in the American channel of the St. Lawrence River, reachable only by private boat or commercial tour vessel. No bridge connects Heart Island to either shore. Canadian operators coordinate manifests with Customs and Border Protection, allowing international passengers to disembark directly at the island's stone quay without returning to a mainland port of entry. A valid passport or enhanced driver's license is required; customs officers station themselves at the island's arrival pavilion during peak months.
The main castle rises from bedrock terraces planted with hybrid tea roses and clipped boxwood allées, its Indiana limestone façade modeled on the Rhineland palaces Boldt and his architect studied during European tours. The ground floor holds the grand hall, billiard room, and library; the second and third floors contain bedroom suites with Circassian walnut paneling and en-suite marble baths; the fourth and fifth levels house servants' quarters and storage; the sixth floor opens onto the rooftop belvedere, offering 360-degree views of the American and Canadian channels. The Yacht House stands 600 feet east, a three-storey boathouse with living quarters above two covered slips and a collection of restored mahogany runabouts. Alster Tower, a diminutive stone playhouse on a separate islet, replicates a medieval Swedish fortress and required its own causeway.
Restoration continues each off-season. The Bolt family never returned after 1904, and decades of exposure stripped interior finishes and allowed weather into the upper floors. Craftsmen have reinstalled parquet, reglazed lancet windows, and reconstructed plaster cornices using archival photographs and surviving fragments. The castle remains a working site; scaffolding and tarpaulins mark active restoration zones, and certain rooms display before-and-after comparisons rather than period furnishings.
4 hr
