Contained within the 3rd Edition (1957) of the Atlas of Canada is a map that shows the density of the Canadian population for 1951. The first map display Western provinces, while the second map concentrates on southern Ontario and the Maritimes. Only the most populous areas are covered. Population density is illustrated by denoting the number of inhabitants per square mile. It shows a significant difference in the population distribution across Canada, mainly in urban and metropolitan areas. The cities with greater inhabitants are clusters within Capital cities, and a even larger concentration south, near the U.S. border, in particular along ocean or inland coastlines.