Banks Island, c.26,000 sq mi (67,340 sq km), NW Northwest Territories, Canada, in the Arctic Ocean, in the Arctic Archipelago. It is the westernmost of the group and is separated from the mainland by Amundsen Gulf. Banks Island, which has many lakes, is a hilly plateau rising to c.2,000 ft (610 m) in the south. Once inhabited by Inuit, it is now uninhabited except for occasional trappers. British explorer Sir Robert McClure discovered that it was an island in 1851. Canadian explorer Vilhjalmur Stefansson spent much time (1914–17) there and explored the interior.