King William Island, part of the Arctic Archipelago, in the Arctic Ocean, Nunavut Territory, Canada, between Boothia Peninsula and Victoria Island. The northern coast of the island was explored (1831) by Sir James C. Ross. In 1837, Thomas Simpson of the Hudson's Bay Company traced the southern coast. The ships of the expedition of Sir John Franklin were wrecked off the west coast, and the island was further explored by searchers for Franklin, notably John Rae and Sir Francis L. McClintock. Roald Amundsen wintered there in 1903–4 while on his way through the Northwest Passage.
See P. F. Cooper, Island of the Lost (1961).