The act was inspired by Lord Durham's report. Lord Durham was sent to the colonies to examine the causes of the Rebellions of 1837 in both Upper and Lower Canada. The union was also proposed to solve pressing financial issues. Mostly through poor investments in canals the government of Upper Canada was bankrupt and deeply in debt. It was hoped its finances could be salvaged by merging it with the still-solvent Lower Canada.
It was also hoped that by merging the rapidly growing anglophone Upper Canada with the slowly growing francophone Lower Canada that in time the French fact in North America would disappear. Thus the act also contained measures banning the French language from official use and ending respect for French institutions such as the civil law and religious education.
The new, merged colony was named the Province of Canada, with Upper Canada renamed as Canada West and Lower Canada as Canada East. Canada West, with its 400 000 inhabitants, was represented by 42 seats in the Legislature's legislative assembly, the same number as the more-populated Canada East, with 600 000 inhabitants. The francophone majority considered this unfair.
Soon after the act was passed the Canadian colony was granted responsible government and under the Baldwin-Lafontaine government many of the more-unfair restrictions were removed.
By the late 1850s the faster growth of the population of Canada West had reversed the population imbalance, and many in Canada West desired representation by population instead of the equal representation mandated by the act.
Dissatisfaction with the Act of Union in both Canadas was one of the factors that led to Canadian Confederation in the 1867.
This political union was similar in nature and in goals to the other Acts of Union enacted by the British Parliament.
External link: Full text of the act
See also: Acts of Union