- The largest river basin in the world by both volume of water and drainage area.
- Drains an area of approximately 7,050,000 square kilometers.
- Flows through Brazil, Peru, Colombia, and Ecuador.
- Numerous tributaries, including the Negro River, Madeira River, and Tapajós River.
2. The Paraná River Basin:
- Second-largest river basin in South America.
- Drains an area of approximately 2,800,000 square kilometers.
- Flows through Brazil, Argentina, Paraguay, and Uruguay.
- Major tributaries include the Paraguay River, Uruguay River, and Iguazu River.
3. The São Francisco River Basin:
- Third-largest river basin in South America.
- Drains an area of approximately 640,000 square kilometers.
- Flows entirely within Brazil.
- Major tributaries include the Rio das Velhas and the Rio Parnaíba.