Canada is a country in the northern half 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 forest and tundra and the Rocky Mountains; about four-fifths of the country's population of 35 million people live near the southern border, and the population is about four-fifths urbanized. The majority of Canada has a cold or severely cold winter climate, but southerly areas are warm in summer.
Canada has been inhabited for millennia by various Aboriginal peoples. Beginning in the 15th and 16th centuries, British and French claims were made on the area, with the colony of Canada first being established by the French in 1537. As a consequence of various conflicts, the United Kingdom gained and lost territories within British North America until it was left, in the late 18th century, with what mostly geographically comprises Canada today. Pursuant to the British North America Act, on July 1, 1867, the colonies of Canada, New Brunswick, and Nova Scotia joined to form the semi-autonomous federal Dominion of Canada. This began an accretion of provinces and territories to the mostly self-governing Dominion to the present ten provinces and three territories forming modern Canada.