The scientific community has been studying for some time a measure capable of quantifying and monitoring the well-being of the population in the territories; this measure cannot be represented exclusively by economic components but also by dimensions that represent different domains of a mainly demographic-social nature. This paper aims to consider well-being from a multidimensional point of view and measure it for the 7983 Italian municipalities in order to highlight differences and similarities. To go down to such a fine territorial detail, it was necessary to use indicators implemented by administrative sources collected in a recently published portal. The application of composite indices allows a one-dimensional measurement that makes a complex phenomenon such as well-being more readable. From a territorial point of view, moreover, the work aims to overcome the administrative division already criticized in literature because it does not allow a reading corresponding to the real behaviors and lifestyles of citizens, embracing a classification more appropriate to the objective of the study. Since the elementary indicators taken into consideration are in some way influenced by reasons of proximity and/or territorial conformation, it was decided to use the classification in Ecoregions of Italy to assess whether the well-being, within the same municipality, “moves” in relation to the municipalities ecologically homogeneous. The results of the analyses present numerous aspects of originality in which the Ecoregions draw an interesting geography of the country.