| Castricum to Octeville | 340.06 mi (547.27 km) |
| Castricum to Oignies | 160.76 mi (258.71 km) |
| Castricum to Oissel | 270.77 mi (435.76 km) |
| Castricum to Olivet | 346.05 mi (556.91 km) |
| Castricum to Ollioules | 652.48 mi (1,050.07 km) |
| Castricum to Olonne-sur-Mer | 505.53 mi (813.58 km) |
| Castricum to Oloron-Sainte-Marie | 690.62 mi (1,111.44 km) |
| Castricum to Onet Village | 573.34 mi (922.71 km) |
| Castricum to Onnaing | 156.31 mi (251.55 km) |
| Castricum to Orange | 581.23 mi (935.40 km) |
| Castricum to Orchies | 155.88 mi (250.87 km) |
| Castricum to Orleans | 343.40 mi (552.66 km) |
| Castricum to Orly | 281.18 mi (452.51 km) |
| Castricum to Ormesson-sur-Marne | 276.25 mi (444.58 km) |
| Castricum to Orsay | 287.43 mi (462.57 km) |
