摘要：The division of a natural territorial system generates new frontiers or limits which demarcate the obtained subsystems. According to the political, economical, military relationships, to the particularity of the physical geographical background of the determined contiguous border sectors, to the character of the support of the state border line, the outlining of some functional cross border systems may have many dimensions. The content of this paper refers to elements of hydrographical, infrastructural and political characters and which, combined all together, generate a various typology of the cross border systems regarding their functionality. The Romanian political area, placed at the EU periphery, the length of the Romanian sector as a component of the Eastern external frontier of the EU (2,172.9 km), offers the best examples of opportunities/barriers on the cross border inter connection way, and whose particularities differs from one inter state sector to the other. Depending on the morphological and morphometrical particularities of the hydrographical support of the frontier's trajectory, and using methods and instruments attested by the geopolitical literature, it had been realized a typology, applied then to the Romania's level and through reference to the Romanian sector of the EU Eastern external border.
关键词：borders; Romania; hydrographical support; EU eastern ex ternal ; border
