| Castelfidardo to Oberkirch | 437.27 mi (703.71 km) |
| Castelfidardo to Obernburg am Main | 487.33 mi (784.29 km) |
| Castelfidardo to Obernkirchen | 641.57 mi (1,032.50 km) |
| Castelfidardo to Oberschleissheim | 344.08 mi (553.74 km) |
| Castelfidardo to Oberstdorf | 315.21 mi (507.28 km) |
| Castelfidardo to Obertraubling | 385.78 mi (620.86 km) |
| Castelfidardo to Obertshausen | 507.54 mi (816.81 km) |
| Castelfidardo to Oberursel | 521.23 mi (838.84 km) |
| Castelfidardo to Ochsenfurt | 458.12 mi (737.28 km) |
| Castelfidardo to Ochsenhausen | 362.44 mi (583.30 km) |
| Castelfidardo to Ochtrup | 671.45 mi (1,080.59 km) |
| Castelfidardo to Odenthal | 603.15 mi (970.67 km) |
| Castelfidardo to Oelde | 630.01 mi (1,013.91 km) |
| Castelfidardo to Oelsnitz | 484.73 mi (780.10 km) |
| Castelfidardo to Oer-Erkenschwick | 636.19 mi (1,023.84 km) |
