| Herzogenrath to Oria | 904.94 mi (1,456.37 km) |
| Herzogenrath to Oristano | 766.80 mi (1,234.04 km) |
| Herzogenrath to Orta Nova | 802.38 mi (1,291.31 km) |
| Herzogenrath to Orte | 652.27 mi (1,049.73 km) |
| Herzogenrath to Ortona | 707.17 mi (1,138.08 km) |
| Herzogenrath to Orvieto | 630.21 mi (1,014.22 km) |
| Herzogenrath to Orzinuovi | 416.89 mi (670.91 km) |
| Herzogenrath to Osimo | 616.16 mi (991.62 km) |
| Herzogenrath to Ospitaletto | 409.91 mi (659.68 km) |
| Herzogenrath to Ostuni | 890.12 mi (1,432.51 km) |
| Herzogenrath to Ottaviano | 799.75 mi (1,287.08 km) |
| Herzogenrath to Ovada | 446.17 mi (718.04 km) |
| Herzogenrath to Ozieri | 723.92 mi (1,165.04 km) |
| Herzogenrath to Paceco | 944.44 mi (1,519.92 km) |
| Herzogenrath to Pachino | 1,073.91 mi (1,728.28 km) |
