Rio Barra Seca is a river located in the northern region of Espírito Santo, Brazil, flowing through the municipalities of Linhares and Jaguaré. Historically shrouded in mystery due to the dense Atlantic Forest that once concealed it, the river remained largely unknown until the 1920s when telegraph line construction first opened access routes between Linhares and São Mateus. Its headwaters originate near Nova Venécia, and the river drains into the Southeast Atlantic Hydrographic Region. The basin encompasses a remarkable range of aquatic environments, from forested upland streams to expansive lowland lakes and seasonal floodplain pools, making it one of the more ecologically diverse river systems in Espírito Santo. The lower stretches of the basin fall within and around the Reserva Biológica (REBIO) de Comboios, while the Vale Natural Reserve (RNV), a privately preserved area, protects portions of the basin as well.