This article focuses on the geographical space between the Amazon delta and the Maroni River (nowadays Brazilian Amapá and French Guiana) in 1600–1730. An imperial frontier between France and Portugal South American possessions, it has been conceptualized as a refuge zone for Amerindians fleeing European colonization. On the contrary, this article argues that the migrations and movements of people toward and within this Amerindian space have to be understood as a continuation of a pre-European set of indigenous networks. Through the reconstruction of multilingual and multiethnic networks, this article brings to light connections and exchanges that make of this space an Amerindian center as well as a European frontier. It analyzes conflicts, gatherings, celebrations, migrations, and alliances between European and Amerindian groups, including the Aruã, Maraon, Arikaré, Palikur, and Galibi. Rather than a refuge zone, this space remained central to Amerindian life and to the upholding of indigenous autonomy due to the maintenance of inter- and intra-ethnic connections and the regular use of routes across this space.