| River Forest to Orbetello | 4,741.92 mi (7,631.38 km) |
| River Forest to Oria | 5,083.10 mi (8,180.45 km) |
| River Forest to Oristano | 4,740.84 mi (7,629.64 km) |
| River Forest to Orta Nova | 4,969.71 mi (7,997.97 km) |
| River Forest to Orte | 4,788.07 mi (7,705.66 km) |
| River Forest to Ortona | 4,872.74 mi (7,841.92 km) |
| River Forest to Orvieto | 4,766.01 mi (7,670.15 km) |
| River Forest to Orzinuovi | 4,567.84 mi (7,351.24 km) |
| River Forest to Osimo | 4,787.36 mi (7,704.51 km) |
| River Forest to Ospitaletto | 4,566.97 mi (7,349.83 km) |
| River Forest to Ostuni | 5,070.44 mi (8,160.09 km) |
| River Forest to Ottaviano | 4,942.05 mi (7,953.46 km) |
| River Forest to Ovada | 4,547.93 mi (7,319.19 km) |
| River Forest to Ozieri | 4,729.60 mi (7,611.55 km) |
| River Forest to Paceco | 4,989.92 mi (8,030.50 km) |
