The chapter examines ‘regional demarcation’ and ‘territorial alteration’, i.e., the mechanisms for the geographical configuration of constituent units laid down in the Italian Constitution. The mechanisms are then part of the ‘territorial constitution’. As they entail a close connection between land, community, and law, they are also the defining features of ‘legal geography’, which outlines the spatial relationship between a community and its territory. Within this theoretical framework, the chapter focuses on how regional demarcation and territorial alteration contribute in shaping the Italian territorial constitution. The chapter outlines the basic features of the territorial demarcation of the Italian regions and considers the mechanisms for the alteration of regional boundaries. Despite the presence of mechanisms for geographical reconfiguration, the Italian territorial constitution has not undergone relevant changes. As a consequence, the narrative of the Italian territorial constitution is one of durability rather than change.