| Clausthal-Zellerfeld to Oria | 854.61 mi (1,375.36 km) |
| Clausthal-Zellerfeld to Oristano | 826.36 mi (1,329.90 km) |
| Clausthal-Zellerfeld to Orta Nova | 766.90 mi (1,234.20 km) |
| Clausthal-Zellerfeld to Orte | 652.74 mi (1,050.48 km) |
| Clausthal-Zellerfeld to Ortona | 680.42 mi (1,095.02 km) |
| Clausthal-Zellerfeld to Orvieto | 633.27 mi (1,019.15 km) |
| Clausthal-Zellerfeld to Orzinuovi | 442.92 mi (712.81 km) |
| Clausthal-Zellerfeld to Osimo | 593.20 mi (954.67 km) |
| Clausthal-Zellerfeld to Ospitaletto | 431.98 mi (695.20 km) |
| Clausthal-Zellerfeld to Ostuni | 838.66 mi (1,349.69 km) |
| Clausthal-Zellerfeld to Ottaviano | 781.96 mi (1,258.44 km) |
| Clausthal-Zellerfeld to Ovada | 501.14 mi (806.51 km) |
| Clausthal-Zellerfeld to Ozieri | 777.81 mi (1,251.77 km) |
| Clausthal-Zellerfeld to Paceco | 961.00 mi (1,546.58 km) |
| Clausthal-Zellerfeld to Pachino | 1,068.24 mi (1,719.16 km) |
