The Oyapock River: Border Between France and Brazil

The Oyapock River: Border Between France and Brazil

The Oyapock River (or Oiapoque River) forms the border between French Guiana (France) and Amapá, Brazil. It is French Guiana's largest river (drainage >20,000 km²), rising in the Tumuc Humac Mountains and flowing 450 km north to the Atlantic east of Oiapoque city.

Heavy rainfall feeds it; many waterfalls and rapids make it non-navigable, contributing to the region's isolation despite mineral and forest wealth.