PARNABA RIVER

Portuguese Rio Parnaba, river, northeastern Brazil, rising in the Serra da Tabatinga and flowing north-northeastward for 1,056 mi (1,700 km) to empty into the Atlantic Ocean, forming a delta at its mouth. In addition to marking the border between the states of Maranho and Piau, the Parnaba has great economic importance. Although its middle and upper reaches are interrupted by waterfalls, it is navigable by shallow-draft vessels from its mouth at least as far south as the junction of the Rio Canind. Important river ports include Piau's three major cities, Teresina (the state capital), Floriano, and Parnaba.