| Grefrath to Navodari | 1,135.20 mi (1,826.92 km) |
| Grefrath to Negresti-Oas | 799.44 mi (1,286.58 km) |
| Grefrath to Nehoiu | 1,001.51 mi (1,611.77 km) |
| Grefrath to Ocna Mures | 863.81 mi (1,390.16 km) |
| Grefrath to Odobesti | 1,018.67 mi (1,639.40 km) |
| Grefrath to Odorheiu Secuiesc | 926.35 mi (1,490.82 km) |
| Grefrath to Oltenita | 1,063.30 mi (1,711.22 km) |
| Grefrath to Onesti | 989.73 mi (1,592.82 km) |
| Grefrath to Oradea | 760.66 mi (1,224.16 km) |
| Grefrath to Orastie | 855.95 mi (1,377.52 km) |
| Grefrath to Oravita | 827.52 mi (1,331.76 km) |
| Grefrath to Orsova | 868.38 mi (1,397.53 km) |
| Grefrath to Otelu Rosu | 834.45 mi (1,342.92 km) |
| Grefrath to Otopeni | 1,022.03 mi (1,644.80 km) |
| Grefrath to Ovidiu | 1,134.93 mi (1,826.49 km) |
