Rio Novo is a river located in the state of Tocantins, Brazil, flowing as part of the greater Rio Tocantins basin. The river originates in the highlands of the Serra Geral de Tocantins region, which serves as a continental divide between the Rio São Francisco basin and the Rio Tocantins basin. This elevated headwater zone is ecologically significant, as the upper reaches of Rio Novo and its tributaries — including the Rio Galheiros — lie in close proximity to the headwaters of the Rio Sapão, a tributary of the Rio São Francisco. This geographic convergence creates a rare "água emendada" (joined waters) phenomenon, where the headwaters of two major river systems nearly meet, making the area a recognized zone of potential fish exchange between two of Brazil's most important river basins.