Arroyo Buñirigo is a Pampean stream located in Buenos Aires Province, Argentina, flowing in permanent contact with the Río de la Plata. This connectivity with one of South America's great river systems defines much of what makes Buñirigo ecologically rich and interesting from an angling perspective. The stream supports a diverse fish assemblage shaped by the influence of the Río de la Plata near its mouth, with species richness and abundance notably higher in the downstream reaches than in the upper stretches. The surrounding Pampean landscape gives the stream its characteristic low-gradient character, typical of the Buenos Aires province waterways.