| Idar-Oberstein to Oegstgeest | 210.97 mi (339.52 km) |
| Idar-Oberstein to Oirschot | 151.86 mi (244.39 km) |
| Idar-Oberstein to Oisterwijk | 159.04 mi (255.95 km) |
| Idar-Oberstein to Oldebroek | 198.90 mi (320.10 km) |
| Idar-Oberstein to Oldenzaal | 180.76 mi (290.91 km) |
| Idar-Oberstein to Ommen | 197.68 mi (318.14 km) |
| Idar-Oberstein to Oosterend | 233.73 mi (376.16 km) |
| Idar-Oberstein to Oosterhout | 171.38 mi (275.81 km) |
| Idar-Oberstein to Oosterwolde | 230.79 mi (371.43 km) |
| Idar-Oberstein to Oostzaan | 215.60 mi (346.97 km) |
| Idar-Oberstein to Opmeer | 230.41 mi (370.81 km) |
| Idar-Oberstein to Oss | 162.27 mi (261.15 km) |
| Idar-Oberstein to Oud-Beijerland | 193.27 mi (311.04 km) |
| Idar-Oberstein to Oudenbosch | 178.20 mi (286.78 km) |
| Idar-Oberstein to Oudewater | 191.68 mi (308.48 km) |
