Offical enumeration date: 4 Apr 1881
These records are held at the Public Archives of Canada, Ottawa, Ontario. Microfilm may be ordered through the nearest Family History Center. Library and Archives Canada has an online search of the 1881 census that provides a .jpg or .pdf image of an individual census page. Library and Archives Canada do not provide an alphabetical index by name to the census. This is available through FamilySearch or Ancestry.
Note that there are numerous WeRelate sources for the 1881 Canadian census in specific localities.
An online index to the 1881 census is available at FamilySearch Record Search (see Source:Canada. Canada Census, 1881 (Index)).