| North Potomac to Oberkirch | 4,079.12 mi (6,564.71 km) |
| North Potomac to Obernburg am Main | 4,083.33 mi (6,571.49 km) |
| North Potomac to Obernkirchen | 4,012.05 mi (6,456.77 km) |
| North Potomac to Oberschleissheim | 4,230.73 mi (6,808.71 km) |
| North Potomac to Oberstdorf | 4,204.66 mi (6,766.74 km) |
| North Potomac to Obertraubling | 4,231.99 mi (6,810.74 km) |
| North Potomac to Obertshausen | 4,064.25 mi (6,540.78 km) |
| North Potomac to Oberursel | 4,049.97 mi (6,517.79 km) |
| North Potomac to Ochsenfurt | 4,126.24 mi (6,640.54 km) |
| North Potomac to Ochsenhausen | 4,170.08 mi (6,711.10 km) |
| North Potomac to Ochtrup | 3,938.95 mi (6,339.13 km) |
| North Potomac to Odenthal | 3,968.04 mi (6,385.95 km) |
| North Potomac to Oelde | 3,986.61 mi (6,415.83 km) |
| North Potomac to Oelsnitz | 4,185.90 mi (6,736.55 km) |
| North Potomac to Oer-Erkenschwick | 3,956.61 mi (6,367.55 km) |
