What is the largest island in a freshwater lake?

Manitoulin Island is the largest island in a freshwater lake, occupying about 2,766 square kilometres in Lake Huron, Canada.

Located in Ontario, Manitoulin separates parts of Lake Huron from Georgian Bay and the North Channel. Its scale is unusual: the island contains 108 freshwater lakes of its own. The largest is Lake Manitou, which covers about 104 square kilometres, making it the world’s largest lake located on a freshwater island. Some of those internal lakes contain islands too, creating famously nested geography.

The island has deep Indigenous and archaeological history. Its name derives from an Odawa or Ojibwe expression associated with a spirit or sacred cave, and archaeological evidence at Sheguiandah records human activity dating back thousands of years. A frequent mix-up is treating “largest freshwater island” as a general island category. The defining detail is that Manitoulin is itself an island inside a freshwater lake; Olkhon, Ukerewe, and Isle Royale are also large freshwater-lake islands, but smaller.