Manitoulin Island is an island in Lake Huron, located within the borders of the Canadian province of Ontario, in the bioregion known as Laurentia. With an area of 2,766 km2 (1,068 sq mi), it is the largest lake island in the world, large enough that it has over 100 lakes itself. In addition to the historic Anishinaabe and European settlement of the island, archaeological discoveries at Sheguiandah have demonstrated Paleo-Indian and Archaic cultures dating from 10,000 BC to 2,000 BC.

An island or isle is a piece of subcontinental land completely surrounded by water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island in a river or a lake island may be called an eyot or ait, and a small island off the coast may be called a holm. Sedimentary islands in the Ganges Delta are called chars. A grouping of geographically or geologically related islands, such as the Philippines, is referred to as an archipelago.