Ironsides Island is a rocky island in the Saint Lawrence River, and part of the Thousand Islands region near Alexandria Bay, New York. It is in both Jefferson and St. Lawrence counties. It was donated by William Browning to the Nature Conservancy in the 1960s[1] to serve as a rookery for Great blue herons. Over a thousand herons return to breed every April.[2] It was declared a National Natural Landmark in April 1967.[3]
The 30-acre (12 ha) island has 30–40-foot (9–12 m) cliffs along its waterfront and has mostly white pine trees.[4] It is near Kring state park.[5]
Prior permission from the Nature Conservancy is required to land on the island,[6] but it can easily be viewed from the water.