The intellectual networks have been little studied and even less has been raised specifically the significance of its borders. Therefore, this essay makes a brief historiographic balance of some work on the borders in the history, the role of the intellectual as a subject of border and the symbolic character of those mentioned in some works of intellectual networks. In a second part, focuses on a particular network, the Latin American Union during its early years (1923-1925), to reflect specifically on two important moments: the one of its foundation to observe how a new network intertwines with other and when an important rupture arises in it and some of its members are separated to form another network. If in the first the border is a porous zone of free transit in the second it becomes an impassable limit of exclusion. &nbsp