The Rio Itajaí-Açu is one of Santa Catarina's most significant river systems, flowing through the heart of the state's lush Atlantic Forest region before emptying into the Atlantic Ocean near the city of Itajaí. Stretching over 130 miles in length, this river drains a vast watershed encompassing numerous municipalities, from the mountainous upper reaches near Ibirama down through the mid-valley towns of Apiúna and Ascurra and into the lower coastal plain. The river is particularly celebrated among fly fishing enthusiasts in southern Brazil, offering a rare opportunity to pursue Rainbow Trout in a tropical country. The surrounding landscape is characterized by dense subtropical vegetation, and the river corridor passes through a mix of agricultural land, small towns, and forested hillsides typical of the German and Italian immigrant-settled interior of Santa Catarina.