| Watford to Octeville | 150.40 mi (242.05 km) |
| Watford to Oignies | 168.42 mi (271.05 km) |
| Watford to Oissel | 172.66 mi (277.87 km) |
| Watford to Olivet | 281.24 mi (452.61 km) |
| Watford to Ollioules | 656.25 mi (1,056.13 km) |
| Watford to Olonne-sur-Mer | 359.11 mi (577.93 km) |
| Watford to Oloron-Sainte-Marie | 584.67 mi (940.93 km) |
| Watford to Onet Village | 522.14 mi (840.30 km) |
| Watford to Onnaing | 194.37 mi (312.81 km) |
| Watford to Orange | 572.25 mi (920.94 km) |
| Watford to Orchies | 177.82 mi (286.17 km) |
| Watford to Orleans | 278.88 mi (448.82 km) |
| Watford to Orly | 235.90 mi (379.64 km) |
| Watford to Ormesson-sur-Marne | 236.86 mi (381.19 km) |
| Watford to Orsay | 234.07 mi (376.70 km) |
