The Rio Ji-Paraná, also known as the Rio Machado, is a significant tributary of the Madeira River flowing through the state of Rondônia in western Brazil. This river system originates in the southeastern border of Rondônia and drains a substantial basin within the state. The region is characterized by its rich biodiversity, particularly within its aquatic ecosystems, and offers anglers a chance to pursue a wide variety of tropical freshwater species. Access to the river is facilitated by nearby towns, and the area supports a basic infrastructure for visiting anglers, including local guides and lodges.