For the last two decades, publications within the ‘‘new regional geography'' have given little emphasis to cartography. This paper examines the specific role of mapping, its political stakes and modalities, in the region-building process. It illustrates this with an analysis of mapping and database production in the institutionalization process of two ‘‘project regions''— the Alps and Carpathian mountains — and in two related, on-going efforts to promote macro-regional strategies. This paper argues that the production of maps and databases deserves to be seen not only as a technical moment, or simply as one output among others in the region-building process, but rather as a component of the process itself, a component that is especially decisive and complex in that it makes explicit the connection between the territorial and the relational dimensions of region-making. The two cases illustrate that mapping is a significant component of the region-making process for three main reasons: (1) it gives shape to the region, provides arguments for its construction, and therefore is a decisive cognitive and rhetorical tool for territorialization; (2) it contributes to the shaping of relational arrangements for the corresponding region; (3) its contribution is important at all different stages in the region-making process – conceptualization, creation, and consolidation – through various modalities