| 100% | IRTYSH | 6 | Main tributary of Siberia's Ob River |
| 68% | IRTYSH | 6 | Main tributary of the Ob River in Russia |
| 54% | IRTISH | 6 | Alternative spelling of River Ob's chief tributary |
| 46% | LACHLAN | 7 | River in SE Australia; main tributary of the Murrumbidgee |
| 42% | NAN | 3 | 460 mile tributary of Thailand's Chao Phraya River |
| 42% | GILA | 4 | Much depleted tributary of the Colorado River |
| 42% | MARNE | 5 | Tributary of the river Seine |
| 42% | GILA | 4 | Tributary of the Colorado River |
| 42% | EBOLA | 5 | Tributary of the Congo River |
| 42% | OSAGE | 5 | Tributary of the Missouri River |
| 41% | BUG | 3 | Tributary of the Narew River forming part of Poland's border with Belarus and Ukraine |
| 40% | BUG | 3 | Tributary of the Narew River forming part of Poland's border with both Belarus and Ukraine |
| 40% | LENA | 4 | River of Siberia |
| 40% | PASHA | 5 | Tributary of the Svir River in NW Russia |
| 40% | YARROW | 6 | Tributary of the River Douglas skirting Chorley, Lancashire |
| 39% | IRRAWADDY | 9 | Main river of burma |
| 39% | DERWENT | 7 | Tributary of the River Trent upon which Derby stands |
| 39% | CHERWELL | 8 | Tributary of the River Thames that flows through Oxford |
| 38% | OTTAWA | 6 | Chief tributary of the St. Lawrence River |
| 38% | KAMA | 4 | Tributary of the Volga River upon which Perm and Solikamsk stand |
| 37% | WHOTHEHELLKNOWS | 15 | Left tributary of the Vitim River in Irkutsk Oblast, Russia |
| 36% | IRTYSH | 6 | River rising in the Altai Mountains; chief tributary of the River Ob |
| 36% | LENA | 4 | Long river of Siberia |
| 36% | GRANTA | 6 | Local name for the longer of two main tributaries of the River Cam in eastern England |
| 36% | WHARFE | 6 | Tributary of the River Ouse in West and North Yorkshire upon which Ilkley stands |
| 35% | IRKUTSK | 7 | One of Siberia's largest cities |
| 35% | BRENT | 5 | Major tributary of the River Thames rising in the London Borough of Barnet |
| 35% | MOHAWK | 6 | Largest tributary of the Hudson River in the state of New York, US |
| 33% | ADANA | 5 | City in S Turkey on the Seyhan River east of Tarsus |
| 33% | IRTYSH | 6 | Asian river rising in the Altai Mountains; chief tributary of the River Ob |