The Dominion of Canada was established on July 1, 1867, when the British North America Act united the provinces of Ontario, Quebec, New Brunswick, and Nova Scotia. This marked the beginning of Canada as a self-governing entity within the British Empire, allowing it to manage its own affairs while still recognizing the British monarch as the head of state. Over the years, Canada expanded to include additional provinces and territories, becoming the second-largest country in the world by land area. The term "Dominion" reflects Canada's status at the time, emphasizing its autonomy while still being part of the Commonwealth of Nations.