The Boothia Peninsula, 32 300 km2, the northernmost tip of mainland North America, juts some 250 km north into the Arctic Archipelago, separated from Somerset Island by Bellot Strait, which is a mere 2 km wide. It is joined to the mainland by an isthmus almost severed by 2 deep inlets and a chain of large lakes. To the east, across the Gulf of Boothia, is Baffin Island. Prince of Wales Island lies to the northwest, across Franklin Strait. The desolate, treeless peninsula is formed on a central spine of Precambrian rock, flanked by flat-bedded limestone lowlands.

Discovered in 1829 by John Ross, it was named for Felix Booth, a distiller who had financed the expedition. Imprisoned in the ice for 3 winters, Ross was forced to abandon his ship Victory and return on foot. His nephew, James C. Ross, later confirmed that Boothia is a peninsula and discovered the north Magnetic Pole on the west side of the peninsula. (The pole has since migrated northward.)

Roald Amundsen travelled the west coast by sled in 1904, and Henry Larsen wintered at Pasley Bay on his successful voyage through the Northwest Passage (1940-42), journeying all around the peninsula by sledge. There is only one community on the peninsula, the hamlet of Taloyoak, which lies on the isthmus.