| Preakness to Orbetello | 4,206.95 mi (6,770.43 km) |
| Preakness to Oria | 4,559.33 mi (7,337.53 km) |
| Preakness to Oristano | 4,178.31 mi (6,724.34 km) |
| Preakness to Orta Nova | 4,443.99 mi (7,151.92 km) |
| Preakness to Orte | 4,257.63 mi (6,852.00 km) |
| Preakness to Ortona | 4,349.21 mi (6,999.38 km) |
| Preakness to Orvieto | 4,236.44 mi (6,817.90 km) |
| Preakness to Orzinuovi | 4,051.02 mi (6,519.49 km) |
| Preakness to Osimo | 4,268.72 mi (6,869.85 km) |
| Preakness to Ospitaletto | 4,051.90 mi (6,520.90 km) |
| Preakness to Ostuni | 4,548.10 mi (7,319.46 km) |
| Preakness to Ottaviano | 4,408.05 mi (7,094.07 km) |
| Preakness to Ovada | 4,020.50 mi (6,470.37 km) |
| Preakness to Ozieri | 4,173.25 mi (6,716.19 km) |
| Preakness to Paceco | 4,429.05 mi (7,127.87 km) |
