| Idar-Oberstein to Oestrich-Winkel | 36.52 mi (58.78 km) |
| Idar-Oberstein to Offenburg | 90.46 mi (145.59 km) |
| Idar-Oberstein to Oftersheim | 61.68 mi (99.27 km) |
| Idar-Oberstein to Ohrdruf | 169.57 mi (272.89 km) |
| Idar-Oberstein to Ohringen | 104.38 mi (167.98 km) |
| Idar-Oberstein to Olbernhau | 274.29 mi (441.43 km) |
| Idar-Oberstein to Olching | 209.48 mi (337.12 km) |
| Idar-Oberstein to Oldenburg | 240.31 mi (386.74 km) |
| Idar-Oberstein to Oldenburg in Holstein | 351.42 mi (565.56 km) |
| Idar-Oberstein to Olfen | 138.59 mi (223.03 km) |
| Idar-Oberstein to Olpe | 93.06 mi (149.76 km) |
| Idar-Oberstein to Olsberg | 124.33 mi (200.09 km) |
| Idar-Oberstein to Oranienburg | 331.31 mi (533.18 km) |
| Idar-Oberstein to Ortenberg | 89.22 mi (143.59 km) |
| Idar-Oberstein to Oschatz | 277.17 mi (446.06 km) |
