Anajás River

The Anajás River (Portuguese: Rio Anajás) is a river of Marajó, an island in the Amazon Delta. It is located in the state Pará in northern Brazil.

Its source is in Ponta de Pedras municipality, in swamp areas called mondongos that flood during the wet season. The river mainly flows west, and its main tributary is the Moções River on its right bank. It joins the Anajás River opposite the main town, also called Anajás. To the south of the river lies an area of flooded igapó forests.

The Anajás is a tidal river. During high tides, it receives water from the Amazon River. Its headwaters and tributaries can become brackish because of the Atlantic Ocean, or they may dry up in the summer.

Excavations show that the Marajoara culture expanded along the Anajás River between 700 and 1100 AD. People lived in river headwaters, lakes, and flooded areas, building dams and reservoirs to control water and platforms for homes and ceremonies.

Since the 1980s, there have been plans to build canals connecting the Anajás to the Atuá River or its tributary the Anabiju to help transport goods between Belém and Macapá, but these plans have not been carried out.