| Mason City to Opwijk | 4,271.57 mi (6,874.43 km) |
| Mason City to Ostend | 4,216.21 mi (6,785.34 km) |
| Mason City to Oud-Heverlee | 4,294.11 mi (6,910.71 km) |
| Mason City to Oud-Turnhout | 4,286.12 mi (6,897.84 km) |
| Mason City to Oudenaarde | 4,255.27 mi (6,848.19 km) |
| Mason City to Oudenburg | 4,220.75 mi (6,792.63 km) |
| Mason City to Oupeye | 4,333.87 mi (6,974.69 km) |
| Mason City to Overijse | 4,291.34 mi (6,906.25 km) |
| Mason City to Overpelt | 4,305.40 mi (6,928.87 km) |
| Mason City to Paal | 4,303.89 mi (6,926.44 km) |
| Mason City to Peer | 4,310.07 mi (6,936.38 km) |
| Mason City to Pepinster | 4,345.77 mi (6,993.83 km) |
| Mason City to Peruwelz | 4,267.75 mi (6,868.28 km) |
| Mason City to Perwez | 4,307.76 mi (6,932.66 km) |
| Mason City to Philippeville | 4,315.20 mi (6,944.64 km) |
