Rio Piauí is a stream flowing through Sergipe, in northeastern Brazil, situated at approximately 11°24′S, 37°24′W. This coastal-region waterway is part of a network of rivers and estuarine systems characteristic of Sergipe's Atlantic coast, where freshwater flows meet brackish and marine influences. The river's position within this transitional zone makes it particularly attractive to species that move between freshwater and saltwater environments, most notably the fat snook — the signature target species for anglers on this water.