| Billings to Orbetello | 5,306.91 mi (8,540.65 km) |
| Billings to Oria | 5,612.49 mi (9,032.44 km) |
| Billings to Oristano | 5,357.35 mi (8,621.82 km) |
| Billings to Orta Nova | 5,507.68 mi (8,863.75 km) |
| Billings to Orte | 5,342.71 mi (8,598.27 km) |
| Billings to Ortona | 5,410.97 mi (8,708.12 km) |
| Billings to Orvieto | 5,320.03 mi (8,561.76 km) |
| Billings to Orzinuovi | 5,107.92 mi (8,220.40 km) |
| Billings to Osimo | 5,320.52 mi (8,562.56 km) |
| Billings to Ospitaletto | 5,103.98 mi (8,214.06 km) |
| Billings to Ostuni | 5,597.75 mi (9,008.71 km) |
| Billings to Ottaviano | 5,496.58 mi (8,845.89 km) |
| Billings to Ovada | 5,107.91 mi (8,220.39 km) |
| Billings to Ozieri | 5,334.87 mi (8,585.64 km) |
| Billings to Paceco | 5,593.42 mi (9,001.74 km) |
