| Watford to Noventa Vicentina | 700.25 mi (1,126.95 km) |
| Watford to Novi di Modena | 697.24 mi (1,122.10 km) |
| Watford to Novi Ligure | 636.00 mi (1,023.55 km) |
| Watford to Nuoro | 910.27 mi (1,464.94 km) |
| Watford to Occhiobello | 719.26 mi (1,157.54 km) |
| Watford to Oderzo | 712.47 mi (1,146.61 km) |
| Watford to Oggiono | 600.69 mi (966.72 km) |
| Watford to Olbia | 877.86 mi (1,412.78 km) |
| Watford to Oleggio | 586.58 mi (944.00 km) |
| Watford to Olgiate Comasco | 587.98 mi (946.26 km) |
| Watford to Olgiate Olona | 592.89 mi (954.17 km) |
| Watford to Omegna | 564.96 mi (909.21 km) |
| Watford to Opera | 616.53 mi (992.21 km) |
| Watford to Oppeano | 687.13 mi (1,105.82 km) |
| Watford to Orbassano | 585.59 mi (942.41 km) |
