Contained within the 4th Edition (1974) of the Atlas of Canada is a set of three maps. The main map shows boundaries of economic regions, census divisions and census metropolitan areas as well as locations of urban centres with national employment offices as of 1961. The designation and labour force served for each centre is denoted. For each economic region the market index for 1961 is shown using a colour coding system. The second map shows populous places in Ontario and Quebec in greater detail (at a scale of 1:5 000 000). The third map shows Northern Canada at a scale of 1:30 000 000.