The growing policy concern with cross-borders migrants tends to overlook the contribution of within-borders migration. Nevertheless, the overwhelming majority of people who move do so inside their own country. In Italy, as well as in other countries, internal migration is a key determinant of changes in population distribution, and the most rapid and effective way to offset imbalances in the local labour markets and to facilitate upward social mobility. This special issue focuses on internal migration in Italy, with the aim of provoking new insights into definitions and categorical boundaries and collecting evidence using a quantitative approach. The four contributions underline that mobility events should be included in analyses of Italian social changes and territorial differences.