Final answer:
Ellesmere Island is the northernmost and largest island in the Canadian Arctic Archipelago, separated from Northern Greenland by the Nares Strait. Cape Columbia is its northernmost point, and Banks Island lies to its west.
Step-by-step explanation:
The northernmost islands in the Canadian Arctic Archipelago include the largest, which is Ellesmere Island. This island is separated from Northern Greenland to the east by the Nares Strait. Cape Columbia, located on Ellesmere Island, is notable for being the northernmost point of Canada. To the west of the Victoria Archipelago lies Banks Island, which is also part of the Canadian Arctic Archipelago but separate from Melville Island.