Canada is a country in the northern part of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres (3.85 million square miles), making it the world's second-largest country by total area and the fourth-largest country by land area. Canada's border with the United States is the world's longest land border. Canada is sparsely populated, the majority of its land territory being dominated by forestand tundra and the Rocky Mountains; about four-fifths of the country's population of 35 million people live near the southern border. The majority of Canada has a cold or severely cold winter climate, but southerly areas are warm in summer.