With its mangled roof of spidery islands and lakes, Canada holds several island-related distinctions. It is home to the world's largest island-in-a-lake (Manitoulin Island in Lake Huron), for example, as well as the world's largest lake-on-an-island (Nettilling Lake on Baffin Island).
Manitoulin Island:
wikipedia
Nettilling Lake
uguelph
Treasure Island, also known as Mindemoya, is a large island in Lake Mindemoya, on Manitoulin Island, which is in Lake Huron. As Manitoulin's largest island, it is said to be the world's largest island in a lake on an island in a lake. The island has no permanent residents, but there are some cottages:
wikipedia
The world's largest island-in-a-lake-on-an-island-in-a-lake-on-an-island is located at exactly 69.793° N, 108.241° W. The nameless island lolls across the center of a small lake, which is itself encapsulated by a slightly larger island. That resides inside one of a series of long finger lakes located 75 miles inland from the southern coast of Victoria Island, a land feature in Northern Canada that is the eighth largest island in the world:
https://www.livescience.com/33679-wo...gle-earth.html
The world's largest island-in-a-lake-on-an-island, however, is the volcanic island of Samosir in the middle of Lake Toba in Sumatra.