| Houghton le Spring to Orbetello | 1,030.65 mi (1,658.66 km) |
| Houghton le Spring to Oria | 1,322.33 mi (2,128.08 km) |
| Houghton le Spring to Oristano | 1,131.54 mi (1,821.04 km) |
| Houghton le Spring to Orta Nova | 1,218.06 mi (1,960.28 km) |
| Houghton le Spring to Orte | 1,059.70 mi (1,705.42 km) |
| Houghton le Spring to Ortona | 1,121.87 mi (1,805.48 km) |
| Houghton le Spring to Orvieto | 1,037.17 mi (1,669.17 km) |
| Houghton le Spring to Orzinuovi | 822.84 mi (1,324.23 km) |
| Houghton le Spring to Osimo | 1,031.10 mi (1,659.39 km) |
| Houghton le Spring to Ospitaletto | 817.70 mi (1,315.96 km) |
| Houghton le Spring to Ostuni | 1,307.65 mi (2,104.46 km) |
| Houghton le Spring to Ottaviano | 1,211.01 mi (1,948.94 km) |
| Houghton le Spring to Ovada | 835.29 mi (1,344.27 km) |
| Houghton le Spring to Ozieri | 1,095.98 mi (1,763.80 km) |
| Houghton le Spring to Paceco | 1,336.97 mi (2,151.64 km) |
