| Wallingford to Orbetello | 856.94 mi (1,379.12 km) |
| Wallingford to Oria | 1,175.91 mi (1,892.44 km) |
| Wallingford to Oristano | 932.06 mi (1,500.00 km) |
| Wallingford to Orta Nova | 1,065.60 mi (1,714.91 km) |
| Wallingford to Orte | 893.73 mi (1,438.32 km) |
| Wallingford to Ortona | 968.06 mi (1,557.94 km) |
| Wallingford to Orvieto | 871.06 mi (1,401.84 km) |
| Wallingford to Orzinuovi | 661.90 mi (1,065.23 km) |
| Wallingford to Osimo | 879.63 mi (1,415.63 km) |
| Wallingford to Ospitaletto | 659.37 mi (1,061.16 km) |
| Wallingford to Ostuni | 1,162.37 mi (1,870.65 km) |
| Wallingford to Ottaviano | 1,048.36 mi (1,687.17 km) |
| Wallingford to Ovada | 657.97 mi (1,058.90 km) |
| Wallingford to Ozieri | 900.69 mi (1,449.53 km) |
| Wallingford to Paceco | 1,151.17 mi (1,852.62 km) |
