A fundamental factor in American life is urbanism, that is, the multiplication and incessant development of large and small towns, to the detriment of the essentially rural population. We are facing a grandiose phenomenon, which is reflected only in the intensely industrial areas of old Europe or in the recently colonized areas of South America and Australia. Overall, the urban population of the United States, according to the 1930 census, is equal to 69 million individuals, or 56.2% of the total. This percentage value is largely exceeded by New England (77.3%), by the Middle Atlantic (77.7%), by the Central NE. (66.4%) and the Pacific (67.5%), while all other divisions remain far below. L’ interdependence between economic and urban conditions could not be more significant. What is most striking, analyzing the figures of the urban population, is the progressive increase of this compared to the rural one, not only in the decidedly industrial states but also in those essentially based on agriculture-pastoral-forestry. In 1890 the percentage of the urban population in the United States was 36.1% (22.7 million individuals). In forty years there are the following variations for the geographical divisions: New England 75.8% and 77.3%; Mid-Atlantic 57.7 and 77.7%; Center NE. 37.8 and 66.4%; South Atlantic 19.5 and 36.1%; Center NO. 25.8 and 41.8%; SE Center. 12.7 and 28.1%; SO Center. 15.1 and 36.4%; Mountain 29.3 and 39.4%; Pacific 42.5 and 67.5%.

In 1930 the 69 million individuals making up the urban population lived in 3,165 centers of which 1332 were under 5000 residents (3.8% of the total population), 851 between 5,000 and 10,000 residents (4.8%), 791 between 10,000 and 50,000 residents (12.6%), 98 with 50,000-100,000 residents (5.3%) and finally 93 centers with more than 100,000 residents alone representing 30% of the total population. Of course, between census and census there is a progressive percentage increase for large centers to the detriment of smaller ones.

The large center therefore occupies a leading role in the North American demographic. It is worth noting here how the various censuses give the population of the center, understood not in a geographical but in an administrative sense. This premise has great value because, as almost always happens, especially in a very young region like the American one, the city understood in a geographical sense is always larger than the administrative one. This is especially true for the metropolises which have seen a large number of centers arise in their immediate vicinity, separated from an administrative point of view, but fully attracted to their demographic and economic orbit.

The examples are truly significant: not only does the city understood in a geographical sense include the neighboring centers, which have sprung up on its outskirts, in the same county and in the same state, but very often it happens that the metropolitan area of ​​the center extends over two contiguous states, as in the case of New York, Kansas City, etc. Thus arises the concept of the geographical area of ​​the city as opposed to that, always inferior, of the administrative city. For various reasons, however, it is necessary to stick to the administrative city in order to make comparisons between the various censuses homogeneous and comparable. Cities with populations over 100,000 residents they added up to 93 in 1930, with a population equal to 30% of the total population of the Union. Also in this case the northeastern states hold the primacy: New England 13 (30%), Mid Atlantic 18 (48%), Central NE. 19 (36% of the total population of the geographical division). Follow the Center NO. with 9 major cities (20%) and the Pacific as well with 9 (40%). It is remarkable to note the importance of urbanization in the western coastal states, in relation to the recent, intense immigration current. The Montagna is the least rich area of ​​large cities due to the special demographic and economic conditions of many states. It should also be noted that in the intensely agricultural regions of the Mississippi basin and in the southern Atlantic states, large cities represent a small percentage of the total population, with the minimum of the Central SE., With 12%. Also in this case, therefore, there is a clear relationship between urban planning and economic conditions. For large cities, see to the respective items;

In a very young region from a historical, social and economic point of view such as the United States, the “water” factor assumes an extraordinary importance in the history of the genesis and development of urban agglomerations, both as an open sea and as a bay, or estuary or river or lake, or navigable canal. Of the 93 centers examined, 51 are located on river arteries more or less suitable for navigation and on artificial canals; 12 on river estuaries, all suitable for navigation, in contact with the sea and usually benefited by the tide; 8 on lakes, 14 on bays, in contact with the open sea: therefore, a better correspondence between physical factor and human centralization could not exist. It is striking at first glance that hardly any large centers have risen directly on the sea, but either in well-sheltered bays (Seattle, Tacoma, San Francisco, Oakland, etc.), or on the estuaries of rivers, which combine the advantage of greater military security with that of the proximity of the ocean and the internal waterway offered by the river: the most significant examples are such respect offered by New York and its satellites, by Philadelphia and Baltimore on the coasts of the Atlantic Ocean, and by Portland on the Pacific coasts. The Great Lakes, a freshwater Mediterranean, are also of great importance, among the busiest and most active for trade and means of communication: there are eight large cities have sprung up on their shores, from Buffalo, the city of milling industry, to Duluth, on Lake Superior, the typical city for exports of iron minerals, through metropolises of the greatest importance for the Union’s economy.

Therefore, there are few North American cities that do not use navigable waterways: other causes of a historical and economic nature have contributed powerfully to their rise, as is the case of San Antonio, in Texas, a frontier city; Birmingham (Alabama, which from a simple village in 1880 became a large city, following the discovery of coal and iron deposits, which made the center a rival of Pittsburgh and the coastal metropolis of the Great Lakes); of Fort Worth and Dallas, both in Texas, of Tulsa in Oklahoma, which owe their recent rapid development to the discovery and exploitation of important oil deposits, etc. A common feature of all these large cities of the Union, when no particular topographical conditions occur, it is their reticulated structure, that is, with wide and straight roads cutting off at right angles: typical examples of New York and Chicago. Traffic requirements, greater availability of space, greater ventilation are all positive factors, which have greatly influenced the use of this particular type of urban plan. Another salient feature is offered by the abundance of areas covered by gardens and parks: in this regard, the primacy is held by Los Angeles. The congested area of ​​many other cities, including New York, where the famous skyscrapers have been built in the City area (skyscrapers), the most significant index of the young American mechanical civilization.

Having grown out of all proportion thanks to immigration, these large cities prominently repeat the ethnic characteristics of the states in which they arose. And also in this case there are very significant differences between the cities of the NE. and the Pacific on one side and the rest on the other. In the former the purely indigenous element is very scarce in comparison with the foreign one or born to totally and partially foreign parents.

Another salient feature of these urban agglomerations is that they arose very recently: only in the states derived from the English excolonies do we go back to the century. XVI: throughout the Far West the date of birth of the great centers is to be placed in the century. XIX and in many cases in the second half: a peculiar difference immediately arises, highlighted by the figures of the various censuses (see table on p. 541), between the Atlantic cities and the Great Lakes on the one hand and the remaining ones by the other: the former show a much more regular demographic increase than the latter.

The growth in the number of large cities is very rapid: 28 were in the whole of the Union in 1890; they rise to 50 in 1910, to 93 in 1930. The great immigration influence, which reached its highest pitch in the period 1900-1914, finds its immediate confirmation also in the multiplication of large cities. All the geographical divisions contribute to this conspicuous increase, but even in these cases the prevalence of lands of recent economic development is noted: while the Middle Atlantic rises from 9 to 18, the NE Center. from 6 to 19, in the SO Center. you jump from 1 to 8 and on the Pacific from 1 to 9: the proportional ratio is to the advantage of the western states, which confirms what was said previously.

The economic structure of large cities is multifaceted: the Atlantic cities of the Center and North are the ones that have more complex structures, such as those that, alongside a very intense maritime life, present many other activities, from steel to mechanical industry, from industry textiles and clothing to publishing. Particular characteristics (textile and mechanical industries, small metal parts) offer most of the large cities of New England, while those of the Great Lakes and the Appalachian area, favored by excellent waterways, the presence of coal on site and supplied with minerals iron coming mainly from the port of Duluth-Superior at the western end of Lake Superior, are above all the cities of the blast furnace, of steel, of specialized mechanical industries. The large centers of inland regions, on the other hand, are intimately linked to the economic activities of their hinterland.

Other notable characteristics of most of these cities are that they are fundamental road and rail nodes, or terminus of the great transcontinental arteries such as Boston, New York, Philadelphia on one side and Seattle, San Francisco, Los Angeles on the other, or internal nodes of the highest interest in the economic history of the North American nation. Chicago, the largest railway hub of the Union, and further south, St Louis, stand out above all, which arose as they are in the zone of forced passage from east to west and from the regions of the Great Lakes to the Gulf of Mexico.