| Clarksburg to Olivares | 3,752.63 mi (6,039.27 km) |
| Clarksburg to Olivenza | 3,668.77 mi (5,904.31 km) |
| Clarksburg to Olot | 4,022.31 mi (6,473.28 km) |
| Clarksburg to Onate | 3,771.26 mi (6,069.26 km) |
| Clarksburg to Onda | 3,961.57 mi (6,375.53 km) |
| Clarksburg to Onteniente | 3,980.37 mi (6,405.79 km) |
| Clarksburg to Orihuela | 3,987.03 mi (6,416.51 km) |
| Clarksburg to Osuna | 3,810.09 mi (6,131.75 km) |
| Clarksburg to Ourense | 3,533.84 mi (5,687.17 km) |
| Clarksburg to Oviedo | 3,603.10 mi (5,798.63 km) |
| Clarksburg to Paiporta | 3,970.65 mi (6,390.14 km) |
| Clarksburg to Pajara | 3,631.03 mi (5,843.57 km) |
| Clarksburg to Palafolls | 4,050.14 mi (6,518.07 km) |
| Clarksburg to Palafrugell | 4,061.43 mi (6,536.23 km) |
| Clarksburg to Palamos | 4,062.08 mi (6,537.28 km) |
