Riacho Pilagá is one of the most celebrated fishing destinations in the province of Formosa, located in the northeastern corner of Argentina. This tributary flows into the mighty Río Paraguay, and its confluence — known locally as "la boca" — is widely regarded as one of the finest fishing mouths in the entire region. The surrounding landscape is quintessentially wild Chaco: dense riparian vegetation, calm backwaters, and a rich aquatic ecosystem that supports an impressive diversity of large sport fish. The area sits at roughly 115 meters above sea level in a tropical climate zone, and the waters here carry the characteristic tannin-stained, moderately turbid quality typical of lowland Chaco river systems. The riacho itself winds through thick vegetation before emptying into the Paraguay, creating a dynamic mixing zone where predatory fish congregate to feed.