Canada has a vast geography that occupies much of the continent of North America, sharing a land border with the contiguous United States to the south and the U.S. state of Alaska to the northwest. Canada stretches from the Atlantic Ocean in the east to the Pacific Ocean in the west; to the north lies the Arctic Ocean. Greenland is to the northeast with a shared border on Hans Island. To the southeast Canada shares a maritime boundary with France's overseas collectivity of Saint Pierre and Miquelon, the last vestige of New France. By total area (including its waters), Canada is the second-largest country in the world, after Russia. By land area alone, however, Canada ranks fourth, the difference being due to it having the world's largest proportion of fresh water lakes. Of Canada's thirteen provinces and territories, only two are landlocked (Alberta and Saskatchewan) while the other eleven all directly border one of three oceans.
Canada is home to the world's northernmost settlement, Canadian Forces Station Alert, on the northern tip of Ellesmere Island—latitude 82.5°N—which lies from the North Pole. Much of the Canadian Arctic is covered by ice and permafrost. Canada has the longest coastline in the world, with a total length of ; additionally, its border with the United States is the world's longest land border, stretching . Three of Canada's Arctic islands, Baffin Island, Victoria Island and Ellesmere Island, are among the ten largest in the world.
Canada can be divided into seven physiographic regions: the Canadian Shield, the interior plains, the Great Lakes-St. Lawrence Lowlands, the Appalachian region, the Western Cordillera, Hudson Bay Lowlands and the Arctic Archipelago. Canada is also divided into fifteen terrestrial and five marine ecozones, encompassing over 80,000 classified species of life. Since the end of the last glacial period, Canada has consisted of eight distinct forest regions, including extensive boreal forest on the Canadian Shield; 42 percent of the land acreage of Canada is covered by forests (approximately 8 percent of the world's forested land), made up mostly of spruce, poplar and pine.