What is the longest river in South America, flowing through Peru and Brazil?

The Amazon River is the longest river in South America, flowing through Peru and Brazil.

The river rises from headwaters in the Andes of Peru and travels eastward across the continent before entering the Atlantic Ocean. Its main channel is generally measured at about 6,400 kilometers, although the exact ranking against the Nile depends on how each river’s source and mouth are defined.

The Amazon has the greatest discharge of any river on Earth. It carries more water into the ocean than the next several largest rivers combined, and its basin covers approximately 7 million square kilometers across several countries. The river and its tributaries support extraordinary biological diversity.

A common mix-up is confusing the Amazon River with the Amazon basin or rainforest. The rainforest occupies a huge region, while the river is its principal waterway. The river is also known by different names along its course, including the Apurímac, Ene, Tambo, Ucayali, and Solimões in parts of its upper and middle system.