The Chapada das Mangabeiras is a mountain range in central Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. The range runs northwest-southeast, and separates the basin of the Tocantins River

Tocantins River

The Tocantins is a river in Brazil, the central fluvial artery of the country. In the Tupi language, its name means "toucan's beak" . It runs from south to north for about 2,640 km. It is not really a branch of the Amazon River, although usually so considered, since its waters flow into the...

 to the southwest from the upper basin of the Parnaiba River

Parnaiba River

The Parnaíba River is a river in Brazil, which forms the border between the states of Maranhão and Piauí. The Parnaíba River rises in the Chapada das Mangabeiras range, and flows northeastward for 1,056 miles to empty into the Atlantic Ocean. The middle and upper regions of this river are...

 to the northeast. The range also forms the boundary between Tocantins state and the states of Maranhão

Maranhão

Maranhão is a northeastern state of Brazil. To the north lies the Atlantic Ocean. Maranhão is neighbored by the states of Piauí, Tocantins and Pará. The people of Maranhão have a distinctive accent...

 and Piauí

Piauí

Piauí is one of the states of Brazil, located in the northeastern part of the country.Piauí has the shortest coastline of any of the non-landlocked Brazilian states at 66 km , and the capital, Teresina, is the only state capital in the north east to be located inland...

. The highest points of both states are located there. The points are unnamed locations, one measuring 804 meters (Maranhão), and the other, 860 meters (Piauí).