| Grefrath to Octeville | 370.13 mi (595.67 km) |
| Grefrath to Oignies | 157.65 mi (253.72 km) |
| Grefrath to Oissel | 269.30 mi (433.40 km) |
| Grefrath to Olivet | 311.49 mi (501.29 km) |
| Grefrath to Ollioules | 566.82 mi (912.21 km) |
| Grefrath to Olonne-sur-Mer | 495.06 mi (796.73 km) |
| Grefrath to Oloron-Sainte-Marie | 649.39 mi (1,045.10 km) |
| Grefrath to Onet Village | 511.83 mi (823.72 km) |
| Grefrath to Onnaing | 136.38 mi (219.48 km) |
| Grefrath to Orange | 502.37 mi (808.48 km) |
| Grefrath to Orchies | 147.45 mi (237.30 km) |
| Grefrath to Orleans | 309.15 mi (497.52 km) |
| Grefrath to Orly | 250.48 mi (403.11 km) |
| Grefrath to Ormesson-sur-Marne | 243.87 mi (392.46 km) |
| Grefrath to Orsay | 259.20 mi (417.15 km) |
