ABSTRACT: This research aims to conduct a study on the problems of a difficult border set as the northern frontier of Old Regime New Spain was, prompting the genesis of a frontier society involving interactions between Spanish settlers and indigenous groups, sometimes facing each other, other times in coexistence and integrated differently within the Spanish Imperial structures. Firstly, this paper analyzes different native groups that populated this region and their forms of integration within a colonial society. Secondly, border areas of interaction are also studied from quite different viewpoints, taking into account what missions and forts (presidios) meant in terms of controlling lands and people. Relations and border disputes led to specific problems in each environment, which are, also, discussed here. The contrast between the different border historical experiences in this area facilitates the global explanations of what the Northern limits of the Spanish Empire in America were and meant.
