| Mainz to Obernburg am Main | 40.16 mi (64.63 km) |
| Mainz to Obernkirchen | 162.00 mi (260.72 km) |
| Mainz to Oberschleissheim | 191.32 mi (307.89 km) |
| Mainz to Oberstdorf | 200.09 mi (322.01 km) |
| Mainz to Obertraubling | 188.66 mi (303.62 km) |
| Mainz to Obertshausen | 25.80 mi (41.53 km) |
| Mainz to Oberursel | 20.50 mi (32.99 km) |
| Mainz to Ochsenfurt | 83.48 mi (134.35 km) |
| Mainz to Ochsenhausen | 152.43 mi (245.31 km) |
| Mainz to Ochtrup | 160.49 mi (258.28 km) |
| Mainz to Odenthal | 88.41 mi (142.28 km) |
| Mainz to Oelde | 127.92 mi (205.87 km) |
| Mainz to Oelsnitz | 175.04 mi (281.71 km) |
| Mainz to Oer-Erkenschwick | 122.90 mi (197.78 km) |
| Mainz to Oerlinghausen | 138.14 mi (222.31 km) |
