| Portici to Oerlinghausen | 815.64 mi (1,312.65 km) |
| Portici to Oestrich-Winkel | 704.32 mi (1,133.49 km) |
| Portici to Offenburg | 614.62 mi (989.14 km) |
| Portici to Oftersheim | 653.66 mi (1,051.96 km) |
| Portici to Ohrdruf | 712.78 mi (1,147.10 km) |
| Portici to Ohringen | 625.12 mi (1,006.03 km) |
| Portici to Olbernhau | 682.08 mi (1,097.70 km) |
| Portici to Olching | 531.14 mi (854.79 km) |
| Portici to Oldenburg | 898.35 mi (1,445.75 km) |
| Portici to Oldenburg in Holstein | 944.95 mi (1,520.76 km) |
| Portici to Olfen | 822.08 mi (1,323.01 km) |
| Portici to Olpe | 770.13 mi (1,239.40 km) |
| Portici to Olsberg | 779.22 mi (1,254.04 km) |
| Portici to Oranienburg | 826.23 mi (1,329.70 km) |
| Portici to Ortenberg | 706.26 mi (1,136.61 km) |
