This article aims to make a discussion about biodiversity and conservation units -"Biodiversity Corridor -that exist in the state of Amapá and their implications in small cities, located in what we call here as a cross-border corridor between Amapá, Brazil; and French Guiana, the overseas territory of France. We will do this by first doing a study of the morphologies and importance of these municipalities, as well as a research of the environmental logic found there, and finally, an analysis of the influences and consequences that these units have been causing in these urban agglomerations, using as a case study the twin cities of Oiapoque and Saint Georges.