Which river joins the Amazon at Manaus?

The Rio Negro joins the Amazon at Manaus, where the two rivers meet at the Meeting of Waters.

At Manaus, the dark, tea-coloured Rio Negro flows alongside the pale, sandy-coloured Solimões River for several kilometres before their waters gradually mix. Downstream, the combined river is generally called the Amazon. This dramatic contrast is caused by differences in temperature, speed, acidity and sediment, not by a sharp physical wall between the rivers.

The Rio Negro is one of the world’s largest blackwater rivers and the largest left-bank tributary of the Amazon. Its water becomes dark after passing through forested areas where decomposing vegetation releases tannins and other organic compounds. Despite its colour, the water is not simply polluted or muddy; blackwater rivers are naturally low in suspended sediment.

Manaus is the capital of Brazil’s Amazonas state and an important gateway to the central Amazon. The Meeting of Waters is both a major tourist attraction and a useful reminder that the Amazon basin is a connected network of enormous rivers. The Xingu, Tapajós and Madeira also join the Amazon system, but they do not form the famous confluence at Manaus.