| WAVENEY | River that forms part of the boundary between Norfolk and Suffolk (7) |
| NIAGARA | River, part of the boundary between Ontario and New York |
| POTOMAC | River that forms part of the borders between Washington, DC and Virginia and between Maryland and Virginia |
| MOSELLE | West-bank tributary of the Rhine River that forms part of the border between Germany and Luxembourg (7) |
| GUAPORE | River that forms part of the border between Brazil and Bolivia (7) |
| MARITSA | River that forms part of the border between Turkey and Greece (7) |
| ORINOCO | River that forms part of the border between Colombia and Venezuela (7) |
| TAMAR | River that forms part of the boundary between Cornwall and Devon (5) |
| OUTLINE | Give a sketchy idea of the boundary of the pitch (7) |
| THEWASH | Inlet between Norfolk and Lincs (3,4) |
| STJOHN | River rising in Maine that forms part of the boundary between USA and Canada (2,4) |
| ODER | River in central Europe that forms part of the boundary between Poland and Germany (4) |
| STLAWRENCE | River which forms part of the boundary between Canada and the U.S. (2,8) |
| NEISSE | Which river forms part of the boundary between Germany and Poland until it flows into the Oder? (6) |
| IRONGATE | One of the names for a scenic 83-mile-long gorge on the Danube forming part of the boundary between Romania and Serbia (4,4) |
| TWEED | Which river forms part of the boundary between Scotland and England? (5) |
| AMUR | What long river forms part of the boundary between China and Russia? (4) |
| STOUR | Major river in East Anglia, part of the boundary between Suffolk and Essex |
| URAL | River forming part of the boundary between Europe and Asia |
| KASAI | Tributary of the Congo River that forms part of the border between the Democratic Republic of the Congo and Angola (5) |
