Happy Canada Day! Canada Day was first called Dominion Day and happens every July 1st. It celebrates Canada's birthday and is anniversary of the 1867 enactment of the British North American Act (now known as the Constitution Act) which united three British colonies into the country of Canada within the British Empire. In 1982, when Canada gained full independence from the United Kingdom it was renamed Canada Day. Canada Day is a great day to get together with family, have fun and celebrate our multicultural and unique country.