| Catonsville to Opwijk | 3,824.49 mi (6,154.91 km) |
| Catonsville to Ostend | 3,766.88 mi (6,062.21 km) |
| Catonsville to Oud-Heverlee | 3,847.47 mi (6,191.90 km) |
| Catonsville to Oud-Turnhout | 3,847.70 mi (6,192.28 km) |
| Catonsville to Oudenaarde | 3,803.80 mi (6,121.63 km) |
| Catonsville to Oudenburg | 3,771.18 mi (6,069.13 km) |
| Catonsville to Oupeye | 3,890.21 mi (6,260.68 km) |
| Catonsville to Overijse | 3,843.36 mi (6,185.29 km) |
| Catonsville to Overpelt | 3,867.66 mi (6,224.40 km) |
| Catonsville to Paal | 3,862.52 mi (6,216.12 km) |
| Catonsville to Peer | 3,871.34 mi (6,230.32 km) |
| Catonsville to Pepinster | 3,901.01 mi (6,278.07 km) |
| Catonsville to Peruwelz | 3,811.56 mi (6,134.11 km) |
| Catonsville to Perwez | 3,858.93 mi (6,210.34 km) |
| Catonsville to Philippeville | 3,859.26 mi (6,210.88 km) |
