| Hartlepool to Orbetello | 1,016.07 mi (1,635.21 km) |
| Hartlepool to Oria | 1,307.73 mi (2,104.59 km) |
| Hartlepool to Oristano | 1,117.49 mi (1,798.43 km) |
| Hartlepool to Orta Nova | 1,203.43 mi (1,936.73 km) |
| Hartlepool to Orte | 1,045.07 mi (1,681.88 km) |
| Hartlepool to Ortona | 1,107.23 mi (1,781.91 km) |
| Hartlepool to Orvieto | 1,022.54 mi (1,645.62 km) |
| Hartlepool to Orzinuovi | 808.20 mi (1,300.68 km) |
| Hartlepool to Osimo | 1,016.45 mi (1,635.83 km) |
| Hartlepool to Ospitaletto | 803.06 mi (1,292.40 km) |
| Hartlepool to Ostuni | 1,293.06 mi (2,080.98 km) |
| Hartlepool to Ottaviano | 1,196.37 mi (1,925.37 km) |
| Hartlepool to Ovada | 820.79 mi (1,320.93 km) |
| Hartlepool to Ozieri | 1,081.79 mi (1,740.97 km) |
| Hartlepool to Paceco | 1,322.52 mi (2,128.39 km) |
