| Castle Pines to Oberkirch | 5,107.77 mi (8,220.16 km) |
| Castle Pines to Obernburg am Main | 5,082.05 mi (8,178.76 km) |
| Castle Pines to Obernkirchen | 4,968.28 mi (7,995.67 km) |
| Castle Pines to Oberschleissheim | 5,237.33 mi (8,428.67 km) |
| Castle Pines to Oberstdorf | 5,234.98 mi (8,424.88 km) |
| Castle Pines to Obertraubling | 5,222.09 mi (8,404.15 km) |
| Castle Pines to Obertshausen | 5,061.36 mi (8,145.48 km) |
| Castle Pines to Oberursel | 5,046.61 mi (8,121.74 km) |
| Castle Pines to Ochsenfurt | 5,121.22 mi (8,241.81 km) |
| Castle Pines to Ochsenhausen | 5,192.23 mi (8,356.09 km) |
| Castle Pines to Ochtrup | 4,909.95 mi (7,901.80 km) |
| Castle Pines to Odenthal | 4,960.67 mi (7,983.43 km) |
| Castle Pines to Oelde | 4,957.59 mi (7,978.47 km) |
| Castle Pines to Oelsnitz | 5,151.67 mi (8,290.80 km) |
| Castle Pines to Oer-Erkenschwick | 4,937.40 mi (7,945.98 km) |
