| Flagstaff to Oberkirch | 5,567.62 mi (8,960.22 km) |
| Flagstaff to Obernburg am Main | 5,538.83 mi (8,913.89 km) |
| Flagstaff to Obernkirchen | 5,420.86 mi (8,724.03 km) |
| Flagstaff to Oberschleissheim | 5,694.16 mi (9,163.87 km) |
| Flagstaff to Oberstdorf | 5,694.40 mi (9,164.25 km) |
| Flagstaff to Obertraubling | 5,677.12 mi (9,136.45 km) |
| Flagstaff to Obertshausen | 5,518.09 mi (8,880.50 km) |
| Flagstaff to Oberursel | 5,503.37 mi (8,856.81 km) |
| Flagstaff to Ochsenfurt | 5,577.37 mi (8,975.91 km) |
| Flagstaff to Ochsenhausen | 5,650.99 mi (9,094.39 km) |
| Flagstaff to Ochtrup | 5,364.62 mi (8,633.52 km) |
| Flagstaff to Odenthal | 5,417.46 mi (8,718.56 km) |
| Flagstaff to Oelde | 5,411.97 mi (8,709.72 km) |
| Flagstaff to Oelsnitz | 5,604.23 mi (9,019.14 km) |
| Flagstaff to Oer-Erkenschwick | 5,393.01 mi (8,679.22 km) |
