| Length (Kilometers) | River | % Correct |
|---|---|---|
| 6,992 | Amazon River | 99%
|
| 2,549 | Paraguay River | 66%
|
| 2,101 | Orinoco River | 58%
|
| 3,180 | Sao Francisco River | 44%
|
| 4,880 | Rio de la Plata | 39%
|
| 3,380 | Madeira River | 38%
|
| 2,250 | Negro River | 33%
|
| 3,650 | Tocantins River | 31%
|
| 2,100 | Xingu River | 26%
|
| 3,211 | Purus River | 23%
|
| 2,615 | Japura River | 16%
|
| 2,410 | Jurua River | 13%
|
| 2,010 | Northern Salado River | 8%
|
| 2,500 | Pilcomayo River | 6%
|
| 2,627 | Araguia River | 2%
|