Which Amazonian river is known as the Solimões before meeting the Negro River at Manaus?

The upper Amazon River is known as the Solimões River in Brazil before it meets the Negro River at Manaus. Downstream from that confluence, the combined river is generally called the Amazon River.

The Meeting of Waters is famous because the Solimões carries pale, sediment-rich water while the Negro carries dark, acidic water stained by dissolved organic matter. The two flows run side by side for several kilometres before mixing more fully.

Naming conventions vary across countries and maps. In Peru and Colombia, the river is usually called the Amazon from a point farther upstream, while Brazilian usage commonly distinguishes the Solimões from the lower Amazon.

The Solimões is not a separate drainage system from the Amazon. It is the principal western branch of the river in Brazil and carries enormous amounts of water and sediment toward the Atlantic. Manaus sits on the north bank near this internationally famous confluence.