| Grefrath to Novi di Modena | 492.12 mi (792.00 km) |
| Grefrath to Novi Ligure | 468.18 mi (753.47 km) |
| Grefrath to Nuoro | 774.72 mi (1,246.79 km) |
| Grefrath to Occhiobello | 504.51 mi (811.93 km) |
| Grefrath to Oderzo | 475.54 mi (765.31 km) |
| Grefrath to Oggiono | 407.51 mi (655.83 km) |
| Grefrath to Olbia | 735.46 mi (1,183.61 km) |
| Grefrath to Oleggio | 409.96 mi (659.77 km) |
| Grefrath to Olgiate Comasco | 401.96 mi (646.89 km) |
| Grefrath to Olgiate Olona | 410.82 mi (661.14 km) |
| Grefrath to Omegna | 388.72 mi (625.58 km) |
| Grefrath to Opera | 431.89 mi (695.07 km) |
| Grefrath to Oppeano | 472.46 mi (760.34 km) |
| Grefrath to Orbassano | 440.73 mi (709.29 km) |
| Grefrath to Orbetello | 655.98 mi (1,055.70 km) |
