Its National Wildlife Refuge is located in Lake Erie, northeast of Cedar Point National Wildlife Refuge. In 1937, West Sister Island was established in 1937 "as a refuge and breeding ground for migratory birds and other wildlife...," by President F.D. Roosevelt. West Sister Island is Lake Erie's largest sites protecting a rookery for Great Blue Herons, Cormorants, Great Egrets, and Black-crowned Night Herons. The birds must travel eighteen miles round trip to the mainland marshes, where waters are shallow enough to allow the birds to hunt for food for themselves and their young. Public access is not permitted, except for research purposes.
The geology of West Sister Island consists of glacial fill that lies over a limestone shelf. The island is covered with trees, very tall populations of poison ivy, Solomon's Seal, and other un-hospitable vegetation. It is jointly owned by the U.S. Fish and Wildlife Service and the U.S. Coast Guard, with refuge management being done by the staff at the Ottawa National Wildlife Refuge, under the Federal Wilderness Act.