Library and Archives Canada Releases Census Records

Library and Archives Canada (LAC) has released the 1842 census of Canada West (modern-day Ontario) and the 1842 census of Canada East (modern-day Quebec).

These censuses, like the US censuses before 1850, contain limited information: name of the head of the household, occupation and number of residents in the household as well as a few other pieces of information.     

Here are direct links to the two census databases:
Canada West: http://www.bac-lac.gc.ca/eng/census/1842-canada-west/Pages/1842-canada-west.aspx
Canada East: http://www.bac-lac.gc.ca/eng/census/1842-canada-east/Pages/1842-canada-east.aspx

LAC has also released the 1870 census of Manitoba, which was taken shortly after Manitoba joined Confederation. It contains the names of 12,200 individuals who lived in the region at that time.

Check it out at: http://www.bac-lac.gc.ca/eng/census/1870/Pages/1870.aspx

The first national census of Canada was conducted in 1871, so all of the above predate that event.
All of the databases listed above are free access.