| Watertown to Opwijk | 3,584.53 mi (5,768.75 km) |
| Watertown to Ostend | 3,527.29 mi (5,676.63 km) |
| Watertown to Oud-Heverlee | 3,607.51 mi (5,805.72 km) |
| Watertown to Oud-Turnhout | 3,605.23 mi (5,802.06 km) |
| Watertown to Oudenaarde | 3,565.09 mi (5,737.45 km) |
| Watertown to Oudenburg | 3,531.69 mi (5,683.71 km) |
| Watertown to Oupeye | 3,649.57 mi (5,873.41 km) |
| Watertown to Overijse | 3,603.79 mi (5,799.74 km) |
| Watertown to Overpelt | 3,625.10 mi (5,834.03 km) |
| Watertown to Paal | 3,621.03 mi (5,827.48 km) |
| Watertown to Peer | 3,629.10 mi (5,840.46 km) |
| Watertown to Pepinster | 3,660.77 mi (5,891.43 km) |
| Watertown to Peruwelz | 3,574.36 mi (5,752.38 km) |
| Watertown to Perwez | 3,619.70 mi (5,825.35 km) |
| Watertown to Philippeville | 3,622.26 mi (5,829.46 km) |
