In 1841, on the advice of Lord Durham, the Union Act took effect, uniting Upper and Lower Canada into the Province of Canada. Upper Canada was renamed Canada West and Lower Canada was renamed Canada East. The union put the French of Quebec in a minority, and ultimately proved unworkable. At the time of the union, Upper Canada’s population was about 450,000. Kingston was the capital of the Province of Canada until 1843 when legislation was passed moving the capital to Montreal.

A railway boom in the 1850s made year-round transportation routes a reality, though the boom abruptly ended in 1857. When the American Civil War started in 1861, the population of Canada West was about 1.5 million.

In 1867, Ontario and Quebec again became separate provinces when they joined with Nova Scotia and New Brunswick to form a federal union, the Dominion of Canada, as declared in the British North America Act. The new nation’s capital was Ottawa, an Ontario town on the Quebec border, and the first prime minister was Sir John A. Macdonald.