In 1867, three colonies in British North America, Canada, New Brunswick and Nova Scotia, united to form a "Federal Union" called Canada. In the course of time, all the other British possessions in North America joined or were integrated into the Canadian federation, under circumstances specific to each. Today, Canada includes ten provinces and three territories.

Canada since 1999

Most of the acts that established the provinces and territories of the Canadian federation, are acts of the British Parliament, as the federal union in 1867 did not mark Canada’s independence from Great Britain. Canada’s becoming an independent state was a gradual process. Among the main stages in this evolution are: 1) ratification by the British Parliament of the Statute of Westminster, 1931, which conferred on Canada full authority over its own foreign policy, and 2) ratification, again by the British Parliament, of the Canada Act, 1982, ¹ which notably provided for the "repatriation" of the Constitution, thus granting Canada its political independence. Since 1982, all of Canada's constitutional acts have emanated from the Canadian Parliament.

Act of the British Parliament (one of Canada's constitutional acts) responding to the express desire of the legislative assemblies of three colonies – the Province of Canada (comprising Canada East and Canada West), Nova Scotia and New Brunswick – to establish a "Federal Union" consisting of four provinces: Ontario (Canada West), Quebec (Canada East), Nova Scotia and New Brunswick.

Section 146 of the British North America Act, 1867 allowed for the possibility of the other British possessions in North America – the colonies (Newfoundland, Prince Edward Island, British Columbia), the lands of the Hudson's Bay Company (Rupert's Land), and the vast territories on the northwestern edge of the continent (the North-Western Territory) – being admitted into the federal union by order of the British Crown on addresses from the Parliament of Canada and, in the case of colonies, from their respective legislative assembly.

In 1982, the British North America Act, 1867 was given the name Constitution Act, 1867.

Act of the Parliament of Canada (one of Canada's constitutional laws) which organized a part of the Northwest Territories (the current region of Winnipeg) as a province to be called Manitoba. In 1871, an act of the British Parliament, the British North America Act, 1871, confirmed among other things the power of the Parliament of Canada to establish provinces in territories not included in the provinces and to make provision for administration and government in those territories.

At the request of the Parliament of Canada, this order in council of the British Crown (one of Canada's constitutional laws) sanctioned the annexation of Rupert's Land and the North-Western Territory to Canada. The aggregate of these territories would from then on be called the Northwest Territories.

At the request of the Parliament of Canada and of the Legislative Assembly of British Columbia, this order in council of the British Crown (one of Canada’s constitutional laws) approved the admission of this colony into the Canadian federal union as a province.

At the request of the Parliament of Canada and of the Legislative Assembly of Prince Edward Island, this order of the British Crown (one of Canada's constitutional laws) sanctioned the admission of this colony into the Canadian federal union as a province.

This act of the Parliament of Canada organized the western part of the Northwest Territories, north of the 60^th parallel, into the Yukon Territory.

Acts of the Parliament of Canada (two of Canada's constitutional laws) organizing most of the part of the Northwest Territories south of the 60th parallel into two new provinces called Saskatchewan and Alberta.

Following two referenda in the colony of Newfoundland (which had not had a legislative assembly since 1934) and an address from the Parliament of Canada, the British Parliament approved the union of the oldest British possession in North America with the Canadian federal union, as a province retaining the name of Newfoundland. This law is one of Canada's constitutional laws.

Act of the Parliament of Canada organizing the eastern part of the Northwest Territories into the Territory of Nunavut. The Act came into effect in April 1999.