| Horndean to Orbetello | 821.25 mi (1,321.67 km) |
| Horndean to Oria | 1,145.75 mi (1,843.91 km) |
| Horndean to Oristano | 889.81 mi (1,432.01 km) |
| Horndean to Orta Nova | 1,034.35 mi (1,664.63 km) |
| Horndean to Orte | 859.81 mi (1,383.73 km) |
| Horndean to Ortona | 936.83 mi (1,507.68 km) |
| Horndean to Orvieto | 837.20 mi (1,347.34 km) |
| Horndean to Orzinuovi | 630.51 mi (1,014.70 km) |
| Horndean to Osimo | 849.35 mi (1,366.89 km) |
| Horndean to Ospitaletto | 628.68 mi (1,011.76 km) |
| Horndean to Ostuni | 1,132.53 mi (1,822.62 km) |
| Horndean to Ottaviano | 1,014.74 mi (1,633.06 km) |
| Horndean to Ovada | 622.26 mi (1,001.43 km) |
| Horndean to Ozieri | 859.53 mi (1,383.27 km) |
| Horndean to Paceco | 1,111.84 mi (1,789.33 km) |
