| Letterkenny to Octeville | 448.60 mi (721.95 km) |
| Letterkenny to Oignies | 544.28 mi (875.93 km) |
| Letterkenny to Oissel | 537.79 mi (865.49 km) |
| Letterkenny to Olivet | 640.76 mi (1,031.20 km) |
| Letterkenny to Ollioules | 1,018.06 mi (1,638.41 km) |
| Letterkenny to Olonne-sur-Mer | 636.71 mi (1,024.68 km) |
| Letterkenny to Oloron-Sainte-Marie | 873.07 mi (1,405.07 km) |
| Letterkenny to Onet Village | 863.02 mi (1,388.89 km) |
| Letterkenny to Onnaing | 568.61 mi (915.09 km) |
| Letterkenny to Orange | 932.03 mi (1,499.96 km) |
| Letterkenny to Orchies | 552.66 mi (889.41 km) |
| Letterkenny to Orleans | 638.85 mi (1,028.13 km) |
| Letterkenny to Orly | 607.61 mi (977.86 km) |
| Letterkenny to Ormesson-sur-Marne | 609.84 mi (981.44 km) |
| Letterkenny to Orsay | 603.88 mi (971.85 km) |
