Nhamundá River or Jamundá River (Yamundá River in Spanish) is a river in northern Brazil, which marks part of the northeastern boundary between states of Amazonas and Pará. The 300 km long Nhamundá River originates in the plateau Serra do Jatapu near the division of the Brazilian States of Roraima, Amazonas and Pará, and from there it flows in a southeastern direction, forming the natural division between Amazonas and Pará. It then crosses the Nhamundá-Mapuera Reserve (EG033) before joining the Trombetas River near the city of Oriximiná. The river, which flows through the Lago Nhamundá, is the last major right-hand affluent of the Trombetas River before the Trombetas joins the Amazon River. The mouth is located about 480 km east (downstream on the Amazon) of Manaus.
The three towns on the river's lower reaches (Terra Santa, Nhamundá, and Faro) are accessible only by boat.
Medina, Jose Toribio (2007) The Discovery Of The Amazon: According To The Account of Friar Gaspar De Carvajal and Other Documents. Kessinger Publishing LLC [[Book sources|ISBN978-1432557195]]
Shoumatoff, Alex, In Southern Light, New York, Simon and Schuster, 1986
^Instituto Brasileiro de Geografia e Estatística (1986). Óbidos(PDF) (Topographic map). 1:250,000. Folhas topográficas – 1:250 000. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística. Retrieved October 22, 2020.