Which river is generally considered the longest river in South America?

The Amazon River is generally considered the longest river in South America.

The river flows eastward across the continent before reaching the Atlantic Ocean. Its drainage basin is the largest in the world, extending through Brazil, Peru, Colombia, Bolivia, Ecuador, Venezuela, and Guyana.

The Amazon’s exact ranking against the Nile has been debated because researchers use different definitions of a river’s source and mouth. Within South America, however, the Amazon is unambiguously the continent’s dominant river system by water discharge and basin size.

The river is often confused with the Amazon Basin, which is the much larger drainage region, or with the Amazon rainforest, a connected but not identical ecological area. The river’s main channel and its many tributaries support enormous biological and human diversity.