The Paraguaçu River (Portuguese: Rio Paraguaçu) is a river in Bahia state of eastern Brazil. It runs 500 kilometres (310 mi) from the Chapada Diamantina highlands of central Bahia to its mouth at the Baía de Todos os Santos. The Paraguaçu is the largest river entirely within Bahia. Its banks are fertile and the cities at its mouth are navigable. It was a main route of transportation and communication of the entire region both in the pre-Colonial and Portuguese Colonial period. Its lower reaches are home to the Baía do Iguape Marine Extractive Reserve, created in 2000.