| Heiloo to Orbetello | 763.91 mi (1,229.39 km) |
| Heiloo to Oria | 1,033.78 mi (1,663.71 km) |
| Heiloo to Oristano | 896.07 mi (1,442.09 km) |
| Heiloo to Orta Nova | 933.13 mi (1,501.72 km) |
| Heiloo to Orte | 785.62 mi (1,264.33 km) |
| Heiloo to Ortona | 838.63 mi (1,349.64 km) |
| Heiloo to Orvieto | 763.61 mi (1,228.91 km) |
| Heiloo to Orzinuovi | 550.46 mi (885.88 km) |
| Heiloo to Osimo | 747.64 mi (1,203.22 km) |
| Heiloo to Ospitaletto | 543.41 mi (874.54 km) |
| Heiloo to Ostuni | 1,018.71 mi (1,639.46 km) |
| Heiloo to Ottaviano | 932.34 mi (1,500.45 km) |
| Heiloo to Ovada | 578.36 mi (930.78 km) |
| Heiloo to Ozieri | 854.35 mi (1,374.95 km) |
| Heiloo to Paceco | 1,077.77 mi (1,734.50 km) |
