| Frederick to Opwijk | 3,843.94 mi (6,186.22 km) |
| Frederick to Ostend | 3,786.37 mi (6,093.57 km) |
| Frederick to Oud-Heverlee | 3,866.92 mi (6,223.21 km) |
| Frederick to Oud-Turnhout | 3,866.80 mi (6,223.02 km) |
| Frederick to Oudenaarde | 3,823.42 mi (6,153.20 km) |
| Frederick to Oudenburg | 3,790.69 mi (6,100.52 km) |
| Frederick to Oupeye | 3,909.58 mi (6,291.86 km) |
| Frederick to Overijse | 3,862.87 mi (6,216.70 km) |
| Frederick to Overpelt | 3,886.75 mi (6,255.13 km) |
| Frederick to Paal | 3,881.76 mi (6,247.09 km) |
| Frederick to Peer | 3,890.48 mi (6,261.12 km) |
| Frederick to Pepinster | 3,920.45 mi (6,309.35 km) |
| Frederick to Peruwelz | 3,831.39 mi (6,166.03 km) |
| Frederick to Perwez | 3,878.49 mi (6,241.83 km) |
| Frederick to Philippeville | 3,879.14 mi (6,242.87 km) |
