The 1851 census was enumerated over two years and is most often referred to as the 1851/52 census.
Ontario did not achieve its current borders until 1912. Prior to that, much of the North was caught in a tug of war between Ontario and Manitoba. As a result, if you are seeking ancestors who lived in North-West Ontario or North-East Manitoba you could find them in either province.
If your ancestor lived near the Ontario-Quebec border take note that some border areas of Ontario were enumerated with Quebec census records.
Ontario received its current name in 1867. Prior to 1867 Ontario was known as:
Parts of Ontario were enumerated with Quebec. If your ancestors lived near the Quebec border and you can't locate them in an Ontario census - check Quebec!
The first province-wide census was taken in 1842 but was head of household only. The 1851 census was the first province-wide census to list each member of each household individually.
The first Canada-wide census was taken in 1871 and every ten years henceforth. Starting in 1956 it became every five years. The most recent census was 16 May 2006 and will be released to the public in 2098.
In 2005 the 1911 census was released. The next to be made available will be the 1921 census which will be released in 2013.
Nearly all of the 1881 census was overexposed during microfilming, leaving most records next to impossible to read.
Some census films are extremely difficult to read. Take along a clear coloured plastic sheet (yellow is best) to place over the microfilm screen. Sometimes faint writing appears easier to read on a yellow background. If using a microfilm printer ask if you can photocopy onto coloured paper - bring your own (again, yellow is best)
In the census, ethnic origin was usually that of the father. Therefore if the children within the household had a different ethnicity you could wonder if the father was in fact a step-parent. But… ethnic origin didn't always follow this ‘rule’. For example, in 1861 Samuel Miller was listed as Irish but in 1871 he was Scottish (his father was Irish, his mother Scottish). If there is a difference with origin, make note and follow up using other records.
1851: Enumerated 12 Jan 1852
Indexes and transcripts are NOT exact duplicates of the census. They are interpretations of what the transcriber or indexer saw - you may see things differently, especially if you are familiar with the family that is represented (ie, the transcriber may see Hodward but you may see Woodward). Always obtain a copy of the original census from microfilm for verification. And don’t take an index or transcript at face value. If you believe your ancestor lived in a particular area, but don’t find him in an index or transcript check the source anyway, he may have been overlooked or their name may have been transcribed incorrectly (ie., listed under the H’s instead of W’s) .