| Difficult Run to Orbetello | 4,422.69 mi (7,117.64 km) |
| Difficult Run to Oria | 4,775.49 mi (7,685.40 km) |
| Difficult Run to Oristano | 4,392.06 mi (7,068.34 km) |
| Difficult Run to Orta Nova | 4,660.11 mi (7,499.72 km) |
| Difficult Run to Orte | 4,473.60 mi (7,199.56 km) |
| Difficult Run to Ortona | 4,565.46 mi (7,347.40 km) |
| Difficult Run to Orvieto | 4,452.46 mi (7,165.54 km) |
| Difficult Run to Orzinuovi | 4,267.64 mi (6,868.10 km) |
| Difficult Run to Osimo | 4,485.20 mi (7,218.24 km) |
| Difficult Run to Ospitaletto | 4,268.57 mi (6,869.60 km) |
| Difficult Run to Ostuni | 4,764.32 mi (7,667.44 km) |
| Difficult Run to Ottaviano | 4,623.75 mi (7,441.21 km) |
| Difficult Run to Ovada | 4,236.71 mi (6,818.33 km) |
| Difficult Run to Ozieri | 4,387.54 mi (7,061.06 km) |
| Difficult Run to Paceco | 4,642.78 mi (7,471.83 km) |
