Jean Lawson, a Genealogist on the Quebec Eastern Township Rootsweb forum brought us the following very helpful list of the ‘official enumeration dates’ for each Canadian census. It is possible these dates were ignored in some cases or ages incorrectly calculated but for the most part these would be the dates that were used to calculate ages on the Canadian Census Reports.
‘The dates traditionally given below for each census is the “official
enumeration date”. The actual enumeration could have taken weeks or months
to complete. However, enumerators were instructed to record the information
on the census returns as it existed on the official enumeration date.
1825 Census
The 1825 Census of Lower Canada (Quebec) was taken from June 20 to September 20, 1825.
1831 Census
The 1831 Census of Lower Canada (Quebec) was taken from June 1 to October 1,1831.
1851 Census
The 1851 Census was taken January 12, 1852. The age given on the census is
the age for the NEXT BIRTHDAY (1852), not the age of the person in 1851.
There are columns for deaths during 1851, cause of death, male or female. An Agricultural Census is available for some sections.
1861 Census
The 1861Census was taken January 14, 1861. The age given is the age on their next birthday. Check the whole county in the Agricultural Census, as some of the pages are out of order.
1871 Census
The 1871 Census was taken April 2, 1871. The age given is the age on their
next birthday. Check at the end of each section for deaths during the year.
There are 8 schedules following the main page in each enumeration district.
1881 Census
The 1881 Census was taken April 4, 1881. The age given is the age on their
last birthday. There is no agricultural census.
1891 Census
The 1891 Census was taken April 6, 1891. The age given is the age on their
last birthday. There is no agricultural census.
1901 Census
The 1901 Census was taken March 31, 1901. The age given is the age on their
last birthday. This is the only census that contains actual dates of birth,
which may or may not be correct. It contains the year of immigration. The
relationship to the head of household is also listed.’
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Related:
Using Ancestry: The 1851 Canadian Census
1851 Census of Canada East, Canada West, New Brunswick, and Nova Scotia
Wellington County, Ontario Canada 1851 Census