| Den Helder to Orbetello | 784.12 mi (1,261.92 km) |
| Den Helder to Oria | 1,050.33 mi (1,690.34 km) |
| Den Helder to Oristano | 918.18 mi (1,477.67 km) |
| Den Helder to Orta Nova | 950.59 mi (1,529.82 km) |
| Den Helder to Orte | 804.98 mi (1,295.49 km) |
| Den Helder to Ortona | 856.51 mi (1,378.42 km) |
| Den Helder to Orvieto | 783.06 mi (1,260.21 km) |
| Den Helder to Orzinuovi | 570.38 mi (917.94 km) |
| Den Helder to Osimo | 765.58 mi (1,232.08 km) |
| Den Helder to Ospitaletto | 563.11 mi (906.24 km) |
| Den Helder to Ostuni | 1,035.16 mi (1,665.93 km) |
| Den Helder to Ottaviano | 950.91 mi (1,530.35 km) |
| Den Helder to Ovada | 599.66 mi (965.06 km) |
| Den Helder to Ozieri | 876.22 mi (1,410.14 km) |
| Den Helder to Paceco | 1,098.37 mi (1,767.66 km) |
