King William Island
At the time, King William Island was called King William Land, since it was thought to be adjoined to Boothia. On May 6, 1854, Rae and his two travelling companions reached a promontory on the western coast of Boothia which allowed them to look far west, at which point they realized King William Island was separated from the mainland. Said island protects the strait from the excessive flow of pack ice from the north, making its waters navigable for 19th-century ships.