| Clarksburg to Orbetello | 4,406.39 mi (7,091.40 km) |
| Clarksburg to Oria | 4,758.91 mi (7,658.73 km) |
| Clarksburg to Oristano | 4,376.77 mi (7,043.73 km) |
| Clarksburg to Orta Nova | 4,643.56 mi (7,473.09 km) |
| Clarksburg to Orte | 4,457.16 mi (7,173.10 km) |
| Clarksburg to Ortona | 4,548.82 mi (7,320.62 km) |
| Clarksburg to Orvieto | 4,435.98 mi (7,139.02 km) |
| Clarksburg to Orzinuovi | 4,250.69 mi (6,840.82 km) |
| Clarksburg to Osimo | 4,468.37 mi (7,191.15 km) |
| Clarksburg to Ospitaletto | 4,251.57 mi (6,842.23 km) |
| Clarksburg to Ostuni | 4,747.70 mi (7,640.68 km) |
| Clarksburg to Ottaviano | 4,607.48 mi (7,415.02 km) |
| Clarksburg to Ovada | 4,220.10 mi (6,791.59 km) |
| Clarksburg to Ozieri | 4,372.01 mi (7,036.07 km) |
| Clarksburg to Paceco | 4,627.50 mi (7,447.25 km) |
