Between 1840 and 1898, the United States and Canada reconfigured their geographic and demographic contours. In only the first few decades of this period, the United States added over one million square miles to its territory, gaining tens of thousands of new citizens through these annexations, while African-American men were, at least officially, granted citizenship and the franchise in the wake of the Civil War. In Canada, the provinces of Upper and Lower Canada were united with provinces as far away as British Columbia, and millions of British citizens became members of the new nation of Canada. My project explores the effects of these shifts on American national self-perception. While I analyze events and ideas in both the United States and Canada, the core of my argument is about the United States. Canadian expansion and unification was a continual backdrop to American attempts to dominate the North American continent, serving as both competition for continental domination and as a comparison for new U.S. policies and governmental forms.

Through their acquisition and incorporation of the Far West, the United States and Canada transformed themselves into what I call transcontinental nations. I use this term to emphasize the significance of the acquisition of the Pacific Coast to the development of the nineteenth-century North American nation. A distinctly North American form, the transcontinental nation was created out of the geographic circumstances that led European settlement to begin on the Atlantic Ocean and offered access to the Pacific only by crossing a continent. At the same time, the transcontinental national form was not only geographically determined, but was also fuelled by the nationalistic desire for territorial expansion and international influence that could be gained by settling lands on the Pacific Coast combined with a determination to avoid previous examples of states built over such distances and with such imperialistic goals.

Rather than presenting a conventional comparative study, my dissertation explores changing ideas about U.S. national identity through a focus on the similarities and differences between the development of the United States during the period from 1840 and 1898 and parallel events in other former British settler colonies, particularly Canada. The period between 1848 and 1898 is often seen as a gap in US expansionism, a hiatus between the Manifest Destiny of the early nineteenth century and the formal and informal imperialism of the twentieth. By looking at the parallel processes in the United States and other former British settler colonies, it becomes obvious that during these decades the expansionist energy had not dissipated, but had merely been refocused. The consolidation of transcontinental nations represented a shift in this energy from piecemeal territorial acquisition to concentrated national consolidation. Putting the United States in context with Canadian expansion allows me to avoid the pitfall of treating U.S. expansion as if it were exceptional and puts American territorial growth within the context of its origins in the first decades of British colonialism in North America. It also reflects the substantial parallels between the nineteenth-century transformation of the United States and other former and current settler colonies of the British Empire. Finally, comparing the United States with Canada and other British settler colonies allows me to sidestep an anachronistic consideration of United States expansion in the nineteenth century within the context of its eventual divergence from other nations in the twentieth.