| Letterkenny to Opwijk | 565.90 mi (910.73 km) |
| Letterkenny to Ostend | 510.45 mi (821.49 km) |
| Letterkenny to Oud-Heverlee | 588.53 mi (947.15 km) |
| Letterkenny to Oud-Turnhout | 582.41 mi (937.29 km) |
| Letterkenny to Oudenaarde | 549.56 mi (884.43 km) |
| Letterkenny to Oudenburg | 514.99 mi (828.79 km) |
| Letterkenny to Oupeye | 628.92 mi (1,012.15 km) |
| Letterkenny to Overijse | 585.64 mi (942.49 km) |
| Letterkenny to Overpelt | 602.05 mi (968.91 km) |
| Letterkenny to Paal | 599.36 mi (964.57 km) |
| Letterkenny to Peer | 606.39 mi (975.89 km) |
| Letterkenny to Pepinster | 640.65 mi (1,031.02 km) |
| Letterkenny to Peruwelz | 562.65 mi (905.49 km) |
| Letterkenny to Perwez | 602.02 mi (968.86 km) |
| Letterkenny to Philippeville | 609.80 mi (981.37 km) |
