| Mapuá River | |
| Pushpin Map: | Brazil |
| River System: | Aramá River |
| Source1 Location: | Pará state |
| Mouth Location: | Aramá River |
| Mouth Coordinates: | -1.065°N -50.5505°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
The Mapuá River (Portuguese: Rio Mapuá) is a river of Pará state in north-central Brazil. It is a left tributary of the Aramá River.
The Mapuá River rises on the island of Marajó in the delta region where the Amazon and Tocantins rivers empty into the Atlantic Ocean.It runs along the southern boundary of the Mapuá Extractive Reserve.The Mapuá is a left tributary of the Aramã, which forms the northern boundary of the reserve.The reserve contains sheets of tidal water and mangroves.The reserve is mostly lowland floodplain, with some terra firma in the centre of the territory.