Contained within the 4th Edition (1974) of the Atlas of Canada is a set of three maps. The main map shows the location and extent of census divisions as of 1961. The second map shows the same information for the most populous regions of Ontario and Quebec at a larger scale of 1:5 000 000. These two maps are accompanied by a textual index that references the coding system used to identify the census divisions to corresponding place names. The third map shows Yukon Territory and Northwest Territories and is accompanied by a supplementary text explaining how these areas are treated as census divisions.