| AMUDARYA | River of central Asia forming much of the northern border of Afghanistan; the ancient Oxus (3,5) |
| GLACIERS | Massive ice forms that once covered much of the Northern Hemisphere. |
| AMU | ___ Darya (River of central Asia) |
| IRANIAN | Asian citizen, one arrested crossing western border of Afghanistan (7) |
| LAKEERIE | Northern border of Cleveland |
| BRICK | An adobe or clinker of clay, such as any one of the flettons forming much of 20th-century London; or, a Delft vase, loaf of bread, old-fashioned mobile phone, piece of Lego or wooden toy block, thus s |
| SNAKE | River forming much of the Oregon-Idaho border |
| AMUR | River forming much of the Russia/China border (4) |
| TAMAR | River forming much of the border between Cornwall and Devon (5) |
| URAL | Russian mountain range forming much of the boundary between Asia and Europe. |
| BULGARIA | Country whose northern border is largely defined by the Danube |
| RIOBRAVO | Mexico's northern border river * (8) |
| KASHMIR | Region on the northern border of India and NE Pakistan (7) |
| THECAUCASUS | Mountain range which runs along the northern borders of Georgia and Azerbaijan (3,8) |
| URALMOUNTAINS | Physical feature forming much of the boundary between Europe and Asia |
| INFRINGE | Encroach on one northern border (8) |
| YALU | River of eastern Asia forming most of the natural boundary between China and North Korea (4) |
| UBANGI | Major river of Central Africa which forms the border between the Central African Republic and the Democratic Republic of Congo (6) |
| ILLYRIA | Ancient Balkan country now forming much of Albania (7) |
| ALLIER | North-flowing river of central France that joins the Loire west of the city of Nevers (6) |
