| Horb am Neckar to Oria | 703.09 mi (1,131.52 km) |
| Horb am Neckar to Oristano | 590.04 mi (949.58 km) |
| Horb am Neckar to Orta Nova | 599.21 mi (964.34 km) |
| Horb am Neckar to Orte | 450.50 mi (725.01 km) |
| Horb am Neckar to Ortona | 503.74 mi (810.68 km) |
| Horb am Neckar to Orvieto | 428.74 mi (689.99 km) |
| Horb am Neckar to Orzinuovi | 218.41 mi (351.50 km) |
| Horb am Neckar to Osimo | 412.74 mi (664.24 km) |
| Horb am Neckar to Ospitaletto | 210.02 mi (338.00 km) |
| Horb am Neckar to Ostuni | 688.51 mi (1,108.05 km) |
| Horb am Neckar to Ottaviano | 596.49 mi (959.96 km) |
| Horb am Neckar to Ovada | 262.98 mi (423.23 km) |
| Horb am Neckar to Ozieri | 543.32 mi (874.38 km) |
| Horb am Neckar to Paceco | 748.26 mi (1,204.20 km) |
| Horb am Neckar to Pachino | 872.72 mi (1,404.51 km) |
