Vaupés River (Uaupés River) is a tributary of the Rio Negro in South America. It arises in the Guaviare Department of Colombia, flowing east through Guaviare and Vaupés Departments. It forms part of the international border between Colombia and the Amazonas state of Brazil. On the border it merges with the Papurí River and becomes known as the Uaupés. In 1847 an explorer saw a rapid which hurled its waves in the air, "as if great subaqueous explosions were taking place." The river continues on east until it flows into the Rio Negro at São Joaquim, Amazonas. Vaupés is a blackwater river.