| Romford to Orbetello | 815.94 mi (1,313.13 km) |
| Romford to Oria | 1,128.91 mi (1,816.80 km) |
| Romford to Oristano | 901.25 mi (1,450.42 km) |
| Romford to Orta Nova | 1,019.64 mi (1,640.96 km) |
| Romford to Orte | 850.63 mi (1,368.95 km) |
| Romford to Ortona | 922.21 mi (1,484.15 km) |
| Romford to Orvieto | 827.94 mi (1,332.44 km) |
| Romford to Orzinuovi | 616.77 mi (992.60 km) |
| Romford to Osimo | 833.07 mi (1,340.70 km) |
| Romford to Ospitaletto | 613.60 mi (987.50 km) |
| Romford to Ostuni | 1,115.13 mi (1,794.63 km) |
| Romford to Ottaviano | 1,004.73 mi (1,616.95 km) |
| Romford to Ovada | 617.49 mi (993.76 km) |
| Romford to Ozieri | 867.81 mi (1,396.60 km) |
| Romford to Paceco | 1,114.73 mi (1,793.98 km) |
