East Sister Island Provincial Park is a Lake Erie nature reserve in the western basin, about nine kilometres west of Pelee Island and 20 kilometres from the mainland. Ontario Parks lists the park at 53.02 hectares, established in 1976.
Access is by private boat only, and Ontario Parks warns that navigational hazards exist around the island. There are no visitor facilities, and visiting is discouraged because of possible disturbance to bird colonies, especially from May through August when the heronry is active.
East Sister is the Erie Archipelago island that escaped logging. Ontario Parks says it is less than a kilometre across but supports a rich and distinct ecology.
The island has southern vegetation with plants rare in Canada, including Short's aster and Kentucky coffee tree. Those coffee trees shelter a major breeding colony of great blue herons, black-crowned night herons, and great egrets. Other shorebirds, waterfowl, and snakes also use the island.
The geology is notable too. Glacial scraping removed topsoil and left deep scratches in the bedrock more than 10,000 years ago. Weathering has exposed Silurian and Devonian bedrock roughly 400 to 430 million years old.
Plan around official research, Lake Erie island ecology, heronry protection, rare plant learning, archipelago geology, offshore navigation awareness, and using nearby serviced destinations for actual visitor facilities.
Confirm whether visiting is appropriate, private boat access, navigational hazards, heronry disturbance guidance, seasonal restrictions, no-facility expectations, weather, lake conditions, alerts, and park rules through the official Ontario Parks source before travelling.
Non-operating park in Ontario Parks locator.
