According to the census of April 21, 1931, the density of the population in Italy was on average about 133 inhab. per sq. km. (125 in 1921); but the deviations from this average value are very strong, even looking only at the provinces, as shown in the table on p. 739. A general picture of the density distribution is offered by the annexed map. First of all, it shows an evident influence of the relief: normally the density decreases with increasing height and both in the Alps and in the Apennines above 500 m. usually falls below 50. per sq. km. and above 1000 m. normally under 10. But a careful examination shows that the picture of the distribution of the population in the mountains is very colorful, since, in contrast to the almost empty elevated areas, there are large valleys and basins cultivated even at a considerable height, in which the population often thickens up to overpopulation: just look at the Val di Susa, the valleys confluent to the lakes Maggiore and Como, the Val d’Adige and also some valleys and basins of Umbria and Abruzzo (Foligno, Terni, Sulmona; Fucino). Normally the population also tends to crowd towards the sea, which is quite natural in a country with such an ancient seafaring life as Italy, but this rule also has notable exceptions: in this regard the Sardinian coasts, those of the Southern Tuscany and Lazio, notable stretches of the Ionian coasts, the lagoon coasts of the northern Adriatic, etc. it is enough to look at the Val di Susa, the valleys confluent to the lakes Maggiore and Como, the Val d’Adige and also some Umbrian and Abruzzese valleys and basins (Foligno, Terni, Sulmona; Fucino). Normally the population also tends to crowd towards the sea, which is quite natural in a country with such an ancient seafaring life as Italy, but this rule also has notable exceptions: in this regard the Sardinian coasts, those of the Southern Tuscany and Lazio, notable stretches of the Ionian coasts, the lagoon coasts of the northern Adriatic, etc. it is enough to look at the Val di Susa, the valleys confluent to the lakes Maggiore and Como, the Val d’Adige and also some Umbrian and Abruzzese valleys and basins (Foligno, Terni, Sulmona; Fucino). Normally the population also tends to crowd towards the sea, which is quite natural in a country with such an ancient seafaring life as Italy, but this rule also has notable exceptions: in this regard the Sardinian coasts, those of the Southern Tuscany and Lazio, notable stretches of the Ionian coasts, the lagoon coasts of the northern Adriatic, etc.
It is also observed that in peninsular Italy and in the islands, regions that still have a predominantly agricultural economy, the density of the population in most cases measures the degree of soil productivity: this is how the high-density areas in the valleys can be explained. and hills of Tuscany, Emilia, Campania, Sicily. Maximum values (over 250-300 inhabitants per sq. Km.) Are reached in areas with particularly fertile soil, such as the volcanic hills of the Antiappennino, the Campania plain, the Etna region, while some hilly areas consisting of sterile clays are sparsely populated. ungrateful, landslides, of Sannio, Lucania, Calabria, Sicily, etc. In some cases a considerable industrial development is added to determine the concentration of the population (lower Valdarno, central Liguria,
This factor – the concentration due to industries – then acts to a much greater extent in northern Italy; in Piedmont, Lombardy and Veneto the density therefore reaches very high values, not only in correspondence with the prosperity of agriculture in the flat and hilly regions, but also by virtue of the congestion caused by large industry; Indeed, our map highlights the areas with a prevalent agricultural economy, in which the density usually remains between 100 and 200 inhab. per sq. km., and those with an industrial economy where this last value is exceeded.
Cities are then in themselves, in general, centers of attraction for the population, and make their effect felt also in the surrounding area; this occurs in Italy not only for large centers, whose influence in this sense is also highlighted by the attached charter, but also for numerous smaller towns, which have, for historical reasons, an importance greater than their demographic entity and that in their centuries-old existence they have been able to exercise this appeal.
Our censuses distinguish the population gathered in centers (of any size) from that scattered in the countryside; but this distinction has not always been made with uniform criteria, so that the results are to be accepted as largely approximate.
The following table compares, region by region, the data offered by the 1931 census with those of three previous censuses (1871, 1901, 1921).
Despite the approximate value of the surveys, the high percentage of population scattered in the countryside (Veneto, Emilia, Marche, Umbria, Tuscany) can be pointed out as an evident index of the agricultural character of some regions of northern and central Italy; this percentage is lower where industrial development (Lombardy), or maritime activity (Liguria) or even historical reasons (Piedmont) have favored agglomeration in centers. On the other hand, in southern Italy, due to a complex of causes, which are partly inherited from past eras, the agricultural population also lives agglomerated in centers, often very large, but of a rural nature, where the proportion of the scattered population is very low (Puglia, Lucania, Calabria, islands). But it is also noted that, in the sixty years considered,
These same facts also explain, at least in part, the different physiognomy of the centers. In southern Italy and in the islands, places that should be called cities by population size, sometimes have the appearance of large villages, not only for the absolute prevalence of the population employed in agriculture, but also for the presence, in the nucleus urban, buildings and premises connected with rural occupations or with livestock farming, whereas in northern Italy, centers with a few thousand inhabitants (less than 5000, sometimes less than 2000) have, due to the character of the buildings and streets, due to the presence of a walled enclosure, for the development of industrial and commercial activity, for the explication of intellectual life, etc., the physiognomy of the city.
Moreover, there is an enormous variety in the type of Italian centers, as well as in their situation and planimetric configuration. For many of the major ones, which had various stages of development, these phases can be recognized in the plant itself, up to the most ancient nucleus, often dating back to the Roman age, and often characterized, in this case, by the orthogonal grid. of the streets. But this regular type of grid with square or rectangular meshes does not always denote the origin from centers of the Roman era. In cities of medieval origin, instead, the irregular and complicated layout of the streets is often characteristic, tortuously arranged around a church, a castle or fortress, etc. In the configuration of many plain cities, free to develop in every sense, the influence exerted by the network of highways is usually evident, ie the influence of rivers, especially near bridges or passages. On the hills and in the mountains, the center had to adapt to the relief and developed according to the possibilities offered by this (Cuneo, Siena, Perugia, Potenza are characteristic examples). Reasons for defense have also often determined, especially in central and southern Italy, the situation and also the type of centers (on peaks, on ridges, on spurs, etc.).
Regarding the demographic entity, in 1931, the municipalities with more than 20,000 inhab. there were 244 (out of the total of 7310) and of these only 66 exceeded 50,000 inhab. and 22 the 100,000. The latter, however, gathered 7,165,000 inhabitants, that is about 17.5% of the entire population of Italy. But the centers with more than 20,000 inhab. they were fewer in number; the attached map gives the distribution, also with regard to the height above sea level.
The increase of the big cities was in the century. Very remarkable XIX. In fact, around 1800 there were only 5 cities with more than 100,000 inhabitants. (Naples over 400,000; Palermo over 200,000; Rome 153,000; Venice 140,000; Milan 135,000); in 1871 Turin, Florence, Genoa, Trieste, Bologna, Venice and Messina were added.
The subsequent development of large cities is highlighted by the following table.
In judging the very unequal increase in the centers indicated in the table, it is also necessary to take into account the recent enlargement of some of them by aggregation of neighboring municipalities (Genoa, Florence, Milan, Naples, Reggio, Venice). For more details see the individual items.
The tendency to flow from the countryside towards the large centers, although in Italy it has not assumed the proportions shown by states with more intense industrial development (Great Britain, France, Germany), nevertheless seemed to proceed, in the last decades, at an accelerated pace, that it could become disturbing; appropriate measures intervened to curb what was excessive in this trend; in fact, the pace of growth of the major cities has slowed down for some years.