| Harpenden to Noventa Vicentina | 705.12 mi (1,134.78 km) |
| Harpenden to Novi di Modena | 702.70 mi (1,130.89 km) |
| Harpenden to Novi Ligure | 642.69 mi (1,034.30 km) |
| Harpenden to Nuoro | 918.52 mi (1,478.22 km) |
| Harpenden to Occhiobello | 724.37 mi (1,165.75 km) |
| Harpenden to Oderzo | 716.50 mi (1,153.09 km) |
| Harpenden to Oggiono | 606.34 mi (975.82 km) |
| Harpenden to Olbia | 885.87 mi (1,425.67 km) |
| Harpenden to Oleggio | 592.78 mi (953.99 km) |
| Harpenden to Olgiate Comasco | 593.85 mi (955.71 km) |
| Harpenden to Olgiate Olona | 598.93 mi (963.88 km) |
| Harpenden to Omegna | 571.09 mi (919.08 km) |
| Harpenden to Opera | 622.56 mi (1,001.91 km) |
| Harpenden to Oppeano | 692.16 mi (1,113.92 km) |
| Harpenden to Orbassano | 592.84 mi (954.09 km) |
