| Douglas to Oria | 1,461.82 mi (2,352.58 km) |
| Douglas to Oristano | 1,158.36 mi (1,864.21 km) |
| Douglas to Orta Nova | 1,348.46 mi (2,170.14 km) |
| Douglas to Orte | 1,168.13 mi (1,879.92 km) |
| Douglas to Ortona | 1,251.45 mi (2,014.01 km) |
| Douglas to Orvieto | 1,145.86 mi (1,844.08 km) |
| Douglas to Orzinuovi | 946.88 mi (1,523.86 km) |
| Douglas to Osimo | 1,166.38 mi (1,877.10 km) |
| Douglas to Ospitaletto | 946.40 mi (1,523.09 km) |
| Douglas to Ostuni | 1,449.26 mi (2,332.36 km) |
| Douglas to Ottaviano | 1,322.79 mi (2,128.83 km) |
| Douglas to Ovada | 927.93 mi (1,493.36 km) |
| Douglas to Ozieri | 1,136.22 mi (1,828.56 km) |
| Douglas to Paceco | 1,395.96 mi (2,246.58 km) |
| Douglas to Pachino | 1,553.02 mi (2,499.34 km) |
