New territorial units resulting from urban sprawl processes constitute a major challenge for territorial planning. The aim of this paper is to analyze periurban spaces, focusing on the delimitation and characterization of the urban units arising from urban sprawl processes. The delimitation derives from fractal analysis, where urbanized space is used to detect the limits of the units. The characterization starts with the calculation of eight different indicators, using Geographic Information Systems tools. PCA is used to obtain different dimensions of the urban sprawl phenomenon. Finally, a cluster analysis has been applied to establish a typology of territorial units and facilitate the comparative analysis. The methodology is applied to a case study, the metropolitan area of Valencia. Results show six groups of urbanized spaces, which present different types of urban sprawl structures with different necessities. This applied research can be useful for the spatial planning of the periurban spaces, insofar as it allows the identification of supra-municipal or infra-municipal areas, where it will be possible to improve infrastructures, facilities, or green infrastructure, to empower secondary urban nuclei and to create new inter-municipal cooperation and governance formulas. In addition, the results can constitute a non-administrative territorial basis for the calculation of land occupation indicators that are often used as thresholds for the creation of new residential spaces in regulatory planning documents.