Metropolitan districts include, in addition to the central city or cities, all adjacent and contiguous civil divisions having a density of not less than 150 inhabitants per square mile, and certain civil divisions of less density. The population of the city as a political unit with a definite corporate name is the population within the corporate limits of the city.

Four tables show the total population and area of metropolitan districts together with increase in population since 1920; the sex, color, nativity, and age distribution of the population in the U.S. and in the metropolitan districts; number of males per hundred females, percent foreign-born white, percent negro, and percent under 15 years of age in the population of the central cities and of the area outside, for metropolitan districts; and population in 1920 and 1930, land area, and density for metropolitan districts.

A map and detailed statistics are given for each metropolitan district showing for the entire district and its constituent areas the total population in 1920 and 1930, as well as density, sex, color, nativity and parentage, and age in 1930.