| Severn to Orbetello | 4,384.74 mi (7,056.55 km) |
| Severn to Oria | 4,737.65 mi (7,624.51 km) |
| Severn to Oristano | 4,353.77 mi (7,006.71 km) |
| Severn to Orta Nova | 4,622.25 mi (7,438.80 km) |
| Severn to Orte | 4,435.70 mi (7,138.57 km) |
| Severn to Ortona | 4,527.66 mi (7,286.56 km) |
| Severn to Orvieto | 4,414.58 mi (7,104.58 km) |
| Severn to Orzinuovi | 4,229.99 mi (6,807.51 km) |
| Severn to Osimo | 4,447.49 mi (7,157.54 km) |
| Severn to Ospitaletto | 4,230.96 mi (6,809.07 km) |
| Severn to Ostuni | 4,726.51 mi (7,606.58 km) |
| Severn to Ottaviano | 4,585.78 mi (7,380.10 km) |
| Severn to Ovada | 4,198.90 mi (6,757.47 km) |
| Severn to Ozieri | 4,349.31 mi (6,999.54 km) |
| Severn to Paceco | 4,604.48 mi (7,410.20 km) |
