The Rio São Francisco — affectionately known as "Velho Chico" (Old Chico) — is one of South America's great rivers and Brazil's longest river flowing entirely within its own borders, stretching approximately 2,914 kilometers from its headwaters in the Canastra Mountains of Minas Gerais to its mouth at the Atlantic Ocean near Piaçabuçu on the Alagoas/Sergipe border. Rising at an elevation of 1,450 meters in São Roque de Minas, the river passes through three distinct biomes — Mata Atlântica, Cerrado, and Caatinga — and flows through the states of Minas Gerais, Bahia, Pernambuco, Alagoas, and Sergipe. In Bahia, the river is a defining geographic and cultural feature, threading through the semi-arid interior and forming the backbone of the Vale do São Francisco. With over 140 identified fish species — including a remarkable 113 endemic species representing roughly 60% of the basin's fish fauna — the Rio São Francisco is one of the most biologically significant freshwater fisheries in South America, making it a compelling destination for anglers seeking a truly unique and diverse fishing experience.