| Alton to Orbetello | 831.36 mi (1,337.95 km) |
| Alton to Oria | 1,153.70 mi (1,856.70 km) |
| Alton to Oristano | 902.76 mi (1,452.85 km) |
| Alton to Orta Nova | 1,042.71 mi (1,678.08 km) |
| Alton to Orte | 869.21 mi (1,398.86 km) |
| Alton to Ortona | 945.17 mi (1,521.10 km) |
| Alton to Orvieto | 846.57 mi (1,362.42 km) |
| Alton to Orzinuovi | 638.83 mi (1,028.10 km) |
| Alton to Osimo | 857.30 mi (1,379.68 km) |
| Alton to Ospitaletto | 636.73 mi (1,024.71 km) |
| Alton to Ostuni | 1,140.35 mi (1,835.22 km) |
| Alton to Ottaviano | 1,024.04 mi (1,648.03 km) |
| Alton to Ovada | 632.34 mi (1,017.65 km) |
| Alton to Ozieri | 871.99 mi (1,403.33 km) |
| Alton to Paceco | 1,123.51 mi (1,808.12 km) |
