The first step to the growth of the Canadian state out of the group of British-controlled territories was the establishment and settlement of a colony in the almost vacant area west of the seigneurial belt of Quebec and north of Lakes Ontario and Erie. Rather than continuing to view this land as a frontier-like extension of the Québec-Montréal axis of settlement, it was decided to organize it as the separate province of Upper Canada.
In the interest of topographic clarity the Ottawa River was selected to form most of the boundary between the two Canadas. This meant that the immense territory of Quebec formerly directly administered from Québec City was greatly reduced in size, with Lower Canada consisting mainly of the established axis of the colony/ province along the St Lawrence River. The Ottawa boundary split a socioeconomic region, the Ottawa valley, between two jurisdictions, with consequences keenly felt today. Even the choice, later in the century, of Bytown (Ottawa) as the capital of the country was based partly on the fact that the Ottawa River was the boundary between Canada East and Canada West.
Before the process of territorial integration could begin, however, the continued existence of a British North America had to be defended against the expansionist desires of the republic to the south. American forces attempted several invasions during the war of 1812-1814, whereas, except for raids on border posts, British forces never invaded the northern fringe of the United States. Great Britain was heavily engaged in the wars against Napoleon and could not afford to send massive armies to North America. The major theatre of military action was along the shores of the Great Lakes and the St Lawrence River between Montréal and Lake Huron. Had these areas fallen and remained in American hands, it is probable that there would not have been a Canada as we know it.
Twenty-five years later British North America faced the principal internal threat to its unity and development. In 1837 revolts broke out in both Lower and Upper Canada, in both cases essentially against the system of land tenure and land grants. The major uprising occurred in Lower Canada, with the activities of the Patriotes. The Mackenzie rebellion outside of Toronto was a weak echo, although it enjoyed much rural support. The principal result of the 1837 rebellion – although an unintended one – was the beginning of the process of integration of British North America.
The unification of the various segments of British North America into the Dominion of Canada began with the union of Lower and Upper Canada into the Province of Canada in 1840. Confederation in 1867 brought together Canada and the two colonies which possessed mainland frontage on the Atlantic, Nova Scotia and New Brunswick. The two parts of Canada, Canada East (Lower) and Canada West (Upper), again became distinct and their names changed to Quebec and Ontario respectively. Prince Edward Island did not enter Confederation until 1873, but its entry was not nearly as significant as that of New Brunswick, without which Confederation would have been impossible. By 1873 western Canada had also joined the confederation. Confederation sealed the boundaries of the Maritime provinces, thus settling conclusively that Cape Breton was to remain part of Nova Scotia, whereas Prince Edward Island was to function separately.
To a large extent Canadian nationhood matured and identity evolved in response to Canadian successes during the First and Second World Wars. As part of a British offensive in April 1917, Canadian soldiers captured the heavily fortified Vimy Ridge in northern France. Many historians and writers consider the Canadian victory at Vimy a defining moment for Canada. Similarly, the Second World War was a major turning-point for Canada. Changes occurred in Canada’s relationship with the outside world, in the role of government, in the nature of the economy and society, and in Canadians’ sense of themselves.