- Length: Approximately 6,400 kilometers (4,000 miles)
- Source: Andes Mountains in Peru
- Countries Traversed: Peru, Brazil, Bolivia, Ecuador, Colombia, Venezuela, Guyana
2. Paraná River:
- Length: Approximately 4,880 kilometers (3,030 miles)
- Source: Confluence of the Paranaíba and Grande rivers in Brazil
- Countries Traversed: Brazil, Argentina, Paraguay
3. São Francisco River:
- Length: Approximately 2,900 kilometers (1,800 miles)
- Source: Serra da Canastra mountain range in Brazil
- Countries Traversed: Brazil