Somerset Island is a large, uninhabited island of the Arctic Archipelago, that is part of the Canadian territory of Nunavut. The island is separated from Cornwallis Island and Devon Island to the north by the Parry Channel, from Baffin Island to the east by Prince Regent Inlet, from the Boothia Peninsula to the south by Bellot Strait, and from Prince of Wales Island to the west by Peel Sound. It has an area of 24,786 km2 (9,570 sq mi), making it the 46th largest island in the world and Canada's twelfth largest island.

The Arctic Archipelago, also known as the Canadian Arctic Archipelago, is an archipelago lying to the north of the Canadian continental mainland, excluding Greenland and Iceland.