| AMUR | What long river forms part of the boundary between China and Russia? (4) |
| YALU | River of eastern Asia forming most of the natural boundary between China and North Korea (4) |
| ODER | River in central Europe that forms part of the boundary between Poland and Germany (4) |
| URAL | The --- Mountains form part of the boundary between Europe and Asia (4) |
| NEISSE | Which river forms part of the boundary between Germany and Poland until it flows into the Oder? (6) |
| TWEED | Which river forms part of the boundary between Scotland and England? (5) |
| PERU | The Putumayo River forms part of its northern border |
| SIDE | A line/edge forming part of the boundary of a plane geometric figure; or, one of two or more contesting sports teams or political parties (4) |
| 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) |
| WAVENEY | River that forms part of the boundary between the counties of Norfolk and Suffolk (7) |
| STJOHN | River rising in Maine that forms part of the boundary between USA and Canada (2,4) |
| STLAWRENCE | River which forms part of the boundary between Canada and the U.S. (2,8) |
| NILE | The river forms a sort of line! (4) |
| POTOMAC | What river forms part of the borders between Mary- land and Washington DC? (7) |
| TAMAR | River that forms part of the boundary between Cornwall and Devon (5) |
| SEES | What long-awaited album finally does, to light of day |
| PIER | What long, decked structure is built out over water? (4) |
| ORINOCO | Which river forms part of the border between Venezuela and Colombia? (7) |
| URALS | Mountain range in western Russia; part of the boundary between Europe and Asia. (5) |
| NIAGARA | River, part of the boundary between Ontario and New York |
