Its main course is 1,400 km (870 mi) long and the Parnaíba River Basin covers 344,112 km2 (132,862 sq mi).[1] The Parnaíba River rises in the Chapada das Mangabeiras range, and flows northeastward to empty into the Atlantic Ocean, being the longest river entirely located within Brazil's Northeast Region.[2] The middle and upper regions of this river are separated by waterfalls, but is otherwise navigable.[citation needed]