| Wheat Ridge to Orbetello | 5,500.89 mi (8,852.82 km) |
| Wheat Ridge to Oria | 5,824.11 mi (9,373.00 km) |
| Wheat Ridge to Oristano | 5,528.12 mi (8,896.65 km) |
| Wheat Ridge to Orta Nova | 5,714.88 mi (9,197.21 km) |
| Wheat Ridge to Orte | 5,541.50 mi (8,918.19 km) |
| Wheat Ridge to Ortona | 5,617.37 mi (9,040.29 km) |
| Wheat Ridge to Orvieto | 5,518.93 mi (8,881.86 km) |
| Wheat Ridge to Orzinuovi | 5,311.31 mi (8,547.73 km) |
| Wheat Ridge to Osimo | 5,528.45 mi (8,897.17 km) |
| Wheat Ridge to Ospitaletto | 5,308.65 mi (8,543.45 km) |
| Wheat Ridge to Ostuni | 5,810.16 mi (9,350.54 km) |
| Wheat Ridge to Ottaviano | 5,696.50 mi (9,167.63 km) |
| Wheat Ridge to Ovada | 5,302.66 mi (8,533.81 km) |
| Wheat Ridge to Ozieri | 5,510.76 mi (8,868.71 km) |
| Wheat Ridge to Paceco | 5,771.84 mi (9,288.88 km) |
