In this article, I ask how to interpret the border regime of South America. I reflect on the possible relation between international migration, states and borders in the field of migration studies in order to build analytically situated categories. In order to do so, I use a qualitative methodology based on a set of documents such as final declarations and technical reports of the South American Conference on Migration (sacm), and resolutions of the Southern Common Market (Mercosur) and the Andean Community (can). In order to interpret the border regime, I construct three categories: (i) the border externalization, associated with the regionalization process of migration control policies in South America, (ii) the crossing from one national territory to another, linked to the control at the border points, and (iii) the borders of permanence, associated with the state mechanisms that stipulate the ways of residence. South America, through its regional organizations, constitutes a sub-region of the global border regime, which favors and stimulates organized, planned and integrated migration control policies. At "the borders", such controls identify migrants belonging to a member state of the can, the Mercosur, or an out-of-region migrant. Thereby, the subjects are subordinated under the political stratum of the state to which they belong. The states set a differential mode to enter and stay in a territory according to the national origin of the subjects. [ABSTRACT FROM AUTHOR]