| Ostend to Olympia Heights (Florida) | 4,569.34 mi (7,353.64 km) |
| Ostend to Omaha (Nebraska) | 4,411.48 mi (7,099.59 km) |
| Ostend to On Top of the World Designated Place (Florida) | 4,480.85 mi (7,211.24 km) |
| Ostend to Onalaska (Wisconsin) | 4,108.96 mi (6,612.72 km) |
| Ostend to Oneida (New York) | 3,555.73 mi (5,722.39 km) |
| Ostend to Oneonta (New York) | 3,558.73 mi (5,727.23 km) |
| Ostend to Ontario (California) | 5,530.82 mi (8,900.99 km) |
| Ostend to Ontario (Oregon) | 4,939.82 mi (7,949.87 km) |
| Ostend to Opa-locka (Florida) | 4,556.90 mi (7,333.63 km) |
| Ostend to Opelika (Alabama) | 4,430.59 mi (7,130.35 km) |
| Ostend to Opelousas (Louisiana) | 4,807.27 mi (7,736.56 km) |
| Ostend to Orange (California) | 5,551.19 mi (8,933.78 km) |
| Ostend to Orange (Texas) | 4,894.42 mi (7,876.81 km) |
| Ostend to Orange City (Florida) | 4,447.76 mi (7,157.98 km) |
| Ostend to Orangeburg (South Carolina) | 4,205.92 mi (6,768.77 km) |
