| Preakness to Octeville | 3,439.71 mi (5,535.68 km) |
| Preakness to Oignies | 3,612.43 mi (5,813.64 km) |
| Preakness to Oissel | 3,561.70 mi (5,732.01 km) |
| Preakness to Olivet | 3,634.02 mi (5,848.38 km) |
| Preakness to Ollioules | 3,945.65 mi (6,349.91 km) |
| Preakness to Olonne-sur-Mer | 3,508.74 mi (5,646.78 km) |
| Preakness to Oloron-Sainte-Marie | 3,651.95 mi (5,877.25 km) |
| Preakness to Onet Village | 3,762.56 mi (6,055.25 km) |
| Preakness to Onnaing | 3,639.24 mi (5,856.79 km) |
| Preakness to Orange | 3,868.06 mi (6,225.04 km) |
| Preakness to Orchies | 3,622.55 mi (5,829.92 km) |
| Preakness to Orleans | 3,633.35 mi (5,847.31 km) |
| Preakness to Orly | 3,631.73 mi (5,844.71 km) |
| Preakness to Ormesson-sur-Marne | 3,636.77 mi (5,852.81 km) |
| Preakness to Orsay | 3,624.26 mi (5,832.69 km) |
