Canada Day is the national day of Canada, a federal statutory holiday celebrating the anniversary of the July 1, 1867, enactment of the British North America Act, 1867 (today called the Constitution Act, 1867, in Canada), which united three colonies into a single country called Canada within the British Empire.
Frequently referred to as “Canada’s birthday”, particularly in the popular press, the occasion marks the joining of the British North American colonies of Nova Scotia, New Brunswick, and the Province of Canada into a federation of four provinces (the Province of Canada being divided, in the process, into Ontario and Quebec) on July 1, 1867. Canada became a kingdom in its own right on that date, but the British Parliament kept limited rights of political control over the new country that were shed by stages over the years until the last vestiges were surrendered in 1982 when the Constitution Act patriated the Canadian constitution.
Most communities across the country will host organized celebrations for Canada Day, usually outdoor public events, such as parades, carnivals, festivals, barbecues, air and maritime shows, fireworks, and free musical concerts, as well as citizenship ceremonies for new citizens.
Via – Wikipedia