| Monte Porzio Catone to Oberkirch | 515.79 mi (830.09 km) |
| Monte Porzio Catone to Obernburg am Main | 580.29 mi (933.88 km) |
| Monte Porzio Catone to Obernkirchen | 741.38 mi (1,193.14 km) |
| Monte Porzio Catone to Oberschleissheim | 448.02 mi (721.01 km) |
| Monte Porzio Catone to Oberstdorf | 404.55 mi (651.06 km) |
| Monte Porzio Catone to Obertraubling | 494.67 mi (796.10 km) |
| Monte Porzio Catone to Obertshausen | 599.56 mi (964.90 km) |
| Monte Porzio Catone to Oberursel | 612.32 mi (985.43 km) |
| Monte Porzio Catone to Ochsenfurt | 556.02 mi (894.82 km) |
| Monte Porzio Catone to Ochsenhausen | 452.84 mi (728.78 km) |
| Monte Porzio Catone to Ochtrup | 763.00 mi (1,227.93 km) |
| Monte Porzio Catone to Odenthal | 689.90 mi (1,110.29 km) |
| Monte Porzio Catone to Oelde | 724.60 mi (1,166.13 km) |
| Monte Porzio Catone to Oelsnitz | 594.78 mi (957.21 km) |
| Monte Porzio Catone to Oer-Erkenschwick | 726.04 mi (1,168.45 km) |
