Cornwallis Island, Nunavut, 6995 km2, is located between Bathurst Island and Devon Island in the Arctic Archipelago. It is separated from Somerset Island to the south by Barrow Strait. The island is generally flat, though there are prominent (400 m) cliffs along the east coast. The land surface is strewn with rock debris, cemented by permafrost.
Traces of ancient Inuit camps are common along the south coast. It was discovered by Sir William Parry in 1819 and named for Sir William Cornwallis. An airstrip and High Arctic weather station were established at Resolute on the south coast in 1947. It is now the major communications centre of the Arctic Archipelago and a transshipment point to stations on the ice-bound outer islands.