| Idrija to Octeville | 767.29 mi (1,234.84 km) |
| Idrija to Oignies | 593.32 mi (954.86 km) |
| Idrija to Oissel | 643.55 mi (1,035.69 km) |
| Idrija to Olivet | 585.76 mi (942.69 km) |
| Idrija to Ollioules | 448.33 mi (721.51 km) |
| Idrija to Olonne-sur-Mer | 754.29 mi (1,213.92 km) |
| Idrija to Oloron-Sainte-Marie | 744.45 mi (1,198.08 km) |
| Idrija to Onet Village | 567.66 mi (913.56 km) |
| Idrija to Onnaing | 567.14 mi (912.73 km) |
| Idrija to Orange | 467.56 mi (752.47 km) |
| Idrija to Orchies | 583.71 mi (939.40 km) |
| Idrija to Orleans | 585.76 mi (942.69 km) |
| Idrija to Orly | 575.71 mi (926.52 km) |
| Idrija to Ormesson-sur-Marne | 570.07 mi (917.44 km) |
| Idrija to Orsay | 583.98 mi (939.83 km) |
