Which river basin contains the Amazon Rainforest and is the largest drainage basin on Earth?

The Amazon Basin contains the Amazon Rainforest and is the largest drainage basin on Earth.

A drainage basin is the area from which water flows into a particular river and its tributaries. The Amazon Basin covers roughly 7 million square kilometres, although published figures vary according to how its boundaries are defined. Its central river system drains a huge portion of South America toward the Atlantic Ocean.

The basin includes the Amazon River and major tributaries such as the Madeira, Negro, Japurá, Juruá, Purus, and Tapajós. Rainfall, mountain runoff, groundwater, and seasonal flooding all contribute to its immense water flow.

The basin should not be confused with the forest itself. Parts of the Amazon Basin are savanna, wetlands, farmland, cities, and mountain environments. Likewise, the rainforest extends across ecological regions that do not perfectly match the hydrological boundary.