By 1851, decennial census-taking had been established, but not until 1867 -- with the establishment of Canada as a country -- did census-taking become a constitutional requirement.
It covers Canada East (Quebec), Canada West (Ontario), New Brunswick, and Nova Scotia (while it covers Nova Scotia, many of the files were destroyed, and only census returns are available for the counties of Pictou, some of the county of Halifax, and the town of Kentville).
The census can be searched by geographic location only. It is not a nominally-indexed database, therefore, it is not searchable by family name.
Although not indexed on the LAC website, it is being indexed by volunteers on the Programme de recherche en demographie historique www.prdh.umontreal.ca/census/en, and a nominal list is being created.
Currently, 20% of Canada West and Canada East has been indexed, but the census will not be made available to the public until all of it is indexed. They are looking for volunteers to complete the indexing.
It states on their website, "Since most of the census schedules for Canadian cities in 1852 have been destroyed, the 1852 Canadian census database will best serve researchers interested in the socio-economic characteristics of rural Canadians at the beginning of the modern statistical era in Canada."
This census can also be accessed at the Ancestry.ca website, where it has been available since October 2006.
On this website, the census is completely indexed by name, and is the first census to be taken after the immigration from Ireland due to the Irish Famine. It also allows searches by geographical location.
This is the first time a comprehensive index has been made available, making it possible to find people in Canada without going to the Library and Archives Canada and going through reels and reels of non-indexed microfilm.
The number of names to be indexed is 1,487,802. The population of Canada at that time was just over 2 million, so most of the people are there, but keep in mind that there are parts of the census missing (e.g. Nova Scotia) because they were lost in a fire.
Although the entire census has not been indexed, www.automatedgenealogy.com is using volunteers to transcribe the Canada East (Quebec) and Canada West (Ontario) sections.
The transcribing of the 1851 census was started with New Brunswick in June of 2007, and is nearly done. Canada East and Canada West is complete, but the census of Nova Scotia has not yet been started.
Simply put the full name you are researching in the name box, and you will see their name and age in the census. The full reference of the census is given, and you can take it to the Library and Archives website www.collectionscanada.gc.ca to see the complete census.
As the LAC site says, "The information found on these images can be used to prepare family histories, the history of towns and villages, research immigration trends, and a great deal more."