The archipelago extends some longitudinally and from the mainland to Cape Columbia, the northernmost point on Ellesmere Island. It is bounded on the west by the Beaufort Sea; on the northwest by the Arctic Ocean; on the east by Greenland, Baffin Bay and Davis Strait; and on the south by Hudson Bay and the Canadian mainland. The various islands are separated from each other and the continental mainland by a series of waterways collectively known as the Northwest Passage. Two large peninsulas, Boothia and Melville, extend northward from the mainland.