| Answer | Crossword Clue |
|---|---|
| YSER | French-Belgian river. |
| OISE | Belgian-French river |
| YSER | Belgian-French river. |
| LYS | French-Belgian river |
| LYS | French-Belgian river. |
| YSER | French-Belgian river |
| OISE | French-Belgian river. |
| LYS | Belgian-French river |
| LYS | French-Belgian border river |
| LYS | French-Belgian boundary river |
| LYS | River on French-Belgian boundary |
| LYS | River, part of French-Belgian boundary. |
