| River Grove to Orbetello | 4,741.40 mi (7,630.55 km) |
| River Grove to Oria | 5,082.52 mi (8,179.52 km) |
| River Grove to Oristano | 4,740.45 mi (7,629.02 km) |
| River Grove to Orta Nova | 4,969.14 mi (7,997.06 km) |
| River Grove to Orte | 4,787.53 mi (7,704.79 km) |
| River Grove to Ortona | 4,872.17 mi (7,841.00 km) |
| River Grove to Orvieto | 4,765.47 mi (7,669.28 km) |
| River Grove to Orzinuovi | 4,567.25 mi (7,350.29 km) |
| River Grove to Osimo | 4,786.77 mi (7,703.56 km) |
| River Grove to Ospitaletto | 4,566.37 mi (7,348.87 km) |
| River Grove to Ostuni | 5,069.86 mi (8,159.15 km) |
| River Grove to Ottaviano | 4,941.52 mi (7,952.61 km) |
| River Grove to Ovada | 4,547.39 mi (7,318.32 km) |
| River Grove to Ozieri | 4,729.18 mi (7,610.88 km) |
| River Grove to Paceco | 4,989.52 mi (8,029.86 km) |
