| Answer | Crossword Clue |
|---|---|
| RIOGRANDE | Northern border of Chihuahua |
| POTOMACRIVER | Northern border of Dixie |
| ERIE | Part of Ohio's northern border |
| OREGON | The Columbia River forms much of its northern border |
| ORE | The Columbia R. forms much of its northern border |
| PERU | The Putumayo River forms part of its northern border |
