| River Ridge to Orbetello | 5,379.80 mi (8,657.95 km) |
| River Ridge to Oria | 5,732.84 mi (9,226.12 km) |
| River Ridge to Oristano | 5,346.13 mi (8,603.77 km) |
| River Ridge to Orta Nova | 5,617.45 mi (9,040.41 km) |
| River Ridge to Orte | 5,430.86 mi (8,740.13 km) |
| River Ridge to Ortona | 5,522.84 mi (8,888.16 km) |
| River Ridge to Orvieto | 5,409.76 mi (8,706.16 km) |
| River Ridge to Orzinuovi | 5,224.91 mi (8,408.67 km) |
| River Ridge to Osimo | 5,442.56 mi (8,758.95 km) |
| River Ridge to Ospitaletto | 5,225.78 mi (8,410.08 km) |
| River Ridge to Ostuni | 5,721.70 mi (9,208.18 km) |
| River Ridge to Ottaviano | 5,580.81 mi (8,981.44 km) |
| River Ridge to Ovada | 5,194.09 mi (8,359.07 km) |
| River Ridge to Ozieri | 5,342.63 mi (8,598.13 km) |
| River Ridge to Paceco | 5,596.72 mi (9,007.05 km) |
