http://en.wikipedia.org/wiki/Canada_Day
Canada Day (French: Fête du Canada) is Canada's national holiday, marking the establishment of Canada as a Dominion on July 1, 1867. It is a federal holiday celebrated on July 1, annually (see exception below), by all provincial governments and most businesses across the country.
A day off from work, Canada Day is often a time for outdoor activities in the early Canadian summer. It is also Canada's main patriotic holiday and often referred to as "Canada's birthday", particularly in the popular press.
While it is the date upon which the present Canadian Constitution first came into effect, the first day of July does not commemorate a clear-cut date of "independence" or "founding". Instead, it commemorates the beginning of the establishment of the Canadian confederation through the 1867 British North America Act. The British Parliament still retained several political controls over Canada after 1867, and the country still lacked many of its modern provinces. The date represents the biggest step in the establishment of Canada as a self-governing country, and the beginning of a gradual march towards full independence from Britain, attained with the proclamation of the Constitution Act by Elizabeth II, Queen of Canada, in 1982.