The Arroyo Pepirí Miní o Yabotí Guazú (Oeste) is a significant waterway flowing through the heart of Misiones Province in northeastern Argentina, originating in the Sierra de Misiones near the locality of Paraíso in the Departamento de Guaraní. This stream drains southward through one of the most ecologically intact regions of Argentina before emptying into the Río Uruguay, just a few kilometers downstream from the famous Saltos del Moconá. The stream's basin is one of the most extensive in the province and flows entirely within a landscape protected by the Reserva de la Biósfera Yabotí, the Parque Provincial Moconá, and the Parque Provincial Esmeralda. Approximately 95% of the surrounding terrain is blanketed by Paranaense Atlantic Forest — a dense subtropical jungle characterized by laurel and guatambú tree communities, with remnant patches of Paraná pine in the northwestern reaches. Steep slopes dominate much of the watershed, lending the stream a dynamic, energetic character with a well-defined sequence of pools, rapids, and rocky runs throughout its length.