In the demographic field, the United States is very interested in the variety and vastness of the phenomena. The contrasts between the individual groups of states are profound: thus, with regard to the territorial surface, we range from the lowest figures typical of New England (28,666 sq km), through the intermediate values of the Middle Atlantic, South Atlantic and Central NE. and SE. (all between 85 and 130,000 sq km), to the high figures of the states on the right bank of the Mississippi, the Mountain and the Pacific (192,000 to 283,500 sq km). The inverse relationship between colonial antiquity and the territorial extension of states could not be more significant: a phenomenon that is also encountered in all South American confederations. The states with the oldest political and economic valorisation are those with the smallest surface.
The same contrast, but the reverse, can be seen with regard to the number of residents: out of a total of 122.8 million (1930; 128.4 million in 1936), over 60% live in the Atlantic states and in the area of the Great Lakes (Centro NE.), Which as a surface represent just 23% of the total; depopulated is the mountain and in general the whole area of recent colonization. As an absolute value, the states of the Middle Atlantic (8.7 million residents per state) are at the head, followed by those of the Central NE. (5 million): the minimum values are offered by the intensely agricultural ones of the South Atlantic (1.7); of the Center NO. (1,9), but above all from the Mountain, with an absolute value that still does not reach half a million today (462,000).
But it is above all the population density that best highlights, with the enormous imbalances of the figures, the profound differences between part and part. Alongside the average value of 15.7 residents per sq. km, are the states of New England and the Mid Atlantic, with the highest values (47.4; 98.9), followed at a short distance by those of the Great Lakes and the Ohio basin (39.3). It is the typically industrial area, the best equipped with means of communication, where the mining (coal and oil), blast furnace, mechanical, textile and chemical industries are thriving, where human densification occurs in large urban agglomerations. The intensely agricultural areas of the NO., Of the South, of the South Atlantic have modest values, but also in this regard we note the progressive decrease in density as we proceed towards the Far West, the far west of the first colonizers: states of the South Atlantic, 21.6 residents per sq.km.; states of the SE Center, 21; from the SO Center, 10.7; of the Center NO., 9,8. The mountain has a total of 1.7 residents per sq km: the largely negative morphological and climatic conditions are reflected very well in human densification, with very low values, the most modest in the whole of the Union, Wyoming (0.9), and Nevada (0, 3). The Pacific coastal area is still sparsely populated today: (9.7 residents per sq. Km.): California excels (13.8), which sees its population multiplying not only for the excellent agricultural conditions (Mediterranean climate), but also and above all for mining exploitation.
Overall, therefore, the Union, despite its 122 million residents, a figure that places it in 4th place among the great countries of the Earth, after China (456 million), India (353), the USSR (166), is still a sparsely populated country, even if the formidable immigration flow has consequently brought about an extraordinary increase in population.
The population density in the United States is mainly in direct dependence on economic causes. The high density figures of the counties of the states of Massachusetts, Rhode Island, Connecticut, the states of the Mid Atlantic and many of those bordering the lake Mediterranean are due to industry and the consequent phenomenon of urbanization: here really the densely populated areas (with more than 100 residents per sq. km.) present a solution of continuity, affecting the maritime counties, where the metropolises of Boston, New York, Philadelphia have arisen (and some of these have a density of thousands of residents, like those of New York, where the Borough of Manhattan extends with 36,000 residents per sq. km in 1930), the river basins of Hudson, Delaware, Susquehanna, upper Ohio, where the adverse morphological conditions have been overcome by the presence of large natural arteries, coal and oil fields and where as a result a formidable industry has been able to develop, above all steel and mechanics, which has its world-famous center in Pittsburgh; and this high-density zone continues also in the states of Central NE., especially where fortunate environmental and economic conditions have given rise and developed powerful urban agglomerations, from Buffalo to Milwaukee. Proceeding west, densities above 100 residents reflect limited areas, veritable oases, where large cities have sprung up: this is the case of the densely populated areas of the Mississippi basin and its right tributaries, the Rocky Mountains and the Pacific area, limited to the counties of the great inner cities of Minneapolis, Sao Paulo, Omaha, Saint Louis, Dallas, New Orleans, Denver, Salt Lake City and Pacific metropolises, to name only the most significant examples. Lower and lower densities are found in all intensely agricultural areas, as one proceeds westward, entering the Mississippi basin, going up the eastern flanks of the Rockies: in this regard there is an almost perfect coincidence between human densification and climatic conditions, since west of the 97th meridian, entering the arid region of the Union, the density drops to less than 10 residents per sq. km, reducing to less than 1 in the most ungrateful regions of the Rocky and interposed plateaus, where only oasis irrigation and mineral resources are able to dot the
Populated with immigration currents, which for grandeur and importance are not reflected elsewhere in the history of humanity, the Union still presents itself today as a gigantic crucible, where the lineages, one can say, of all over the Earth. A synthetic look at the current ethnic conditions makes us understand the extent of the phenomenon. According to the 1930 census, out of a total of about 123 million individuals, almost 109 were Whites (88.7%); 11.9 Negroes (9.7 ° 6) and 2 were made up of elements of other races such as Indians, Chinese, Japanese, Mexicans (1.6%).
The white element is therefore the predominant, but in its distribution there are profound differences between part and part of the Union: it constitutes almost the totality of the population in the states of New England (98.8%) with the maximum of New Hampshire (99, 8%), of the Mid Atlantic (95.9%; New York maximum with 96.5%), throughout the Northern Mississippi Basin (Center NE. With 96%; Center NO. With 96.8%; maximum of Iowa with 99.1%), in the Rockies and in the Pacific states (89.2% and 91.5% respectively; the maximum value is offered by Idaho with 98.3%). Very low values are offered by the southern states of the Union (South Atlantic 71.9%; Central SE. 73.1%; Central SO. 74.7%; maximum value of West Virginia with 93.3%; minimum of Mississippi with 49.6%). Here, beside the white element, lives, the result of particular historical and above all climatic and economic needs, the black one (for which see below). To this we must add the Mexican element for 1930, which is more widespread in Texas, Arizona and California, therefore, in the states bordering Mexico.
This formidable mass of Whites came settling in the Union starting from the century. XVI, writing one of the most interesting pages in the history of mankind. It is therefore natural and very appropriate to divide Whites into whites born to indigenous parents, to partially and totally foreign parents, and to those born abroad, made by the censuses: the prevailing in the individual states and in the geographical divisions of one or the other another category clearly shows us the intensity of the immigration phenomenon and the antiquity of the phenomenon itself.
In 1930, out of a total of about 109 million Whites, over 70 million (64.4%) were born to indigenous parents; 25.4 million (23.3%) of partially and totally foreign parents; 13.4 million (12.3%) born abroad. It is precisely the north-eastern states, the theater of an important innovation, that have the lowest numbers of true Americans: New England 39.3%; Mid Atlantic 45.5%; typically industrial states accuse less than a third of homeland-born populations, such as, for example, New York with 36.8% and Rhode Island with 31.2%, the lowest percentage of all the Union. Naturally the proportion increases as one proceeds towards the south or towards the west, entering the typically agricultural states, of more ancient penetration, or where the external immigration phenomenon was less intense. The high values decrease again, proceeding towards the Rocky and Pacific states, where the immigration phenomenon from Europe and Asia was one of the primary causes of their population and magnificent development. The reverse distribution, on the other hand, presents the figures relating to those born to partially and totally foreign parents and to those born abroad, in the sense that they are precisely the states of the NE. those who accuse the highest proportional figures (the state of New York still in 1930 had over ¼ of the entire population born abroad), such as those who have been the scene of a very strong immigration current from Europe, while those of the south warn a very small group of elements born abroad, which for many is reduced to less than 1%. The Mountain states and especially those of the Pacific, on the other hand, experience large numbers of immigrant elements (16.1%, in the states of Washington and California) without, however, equaling the very high figures of New England and the Middle Atlantic.
In this way, the areas of greatest immigration influence are outlined in large sections. Already observing the data in the table, relating to the 1900 and 1930 censuses, we can see for all geographical divisions an increase in the indigenous population to the detriment of the immigrant population, with the exception of New England and the Middle Atlantic, which in the thirty years considered instead saw an increase in the structure of the foreign element, the result of those immigration currents from Europe, which reached the greatest proportions in the decade 1900-1910.