| Catonsville to Oberkirch | 4,051.25 mi (6,519.85 km) |
| Catonsville to Obernburg am Main | 4,055.71 mi (6,527.03 km) |
| Catonsville to Obernkirchen | 3,984.84 mi (6,412.98 km) |
| Catonsville to Oberschleissheim | 4,202.98 mi (6,764.05 km) |
| Catonsville to Oberstdorf | 4,176.73 mi (6,721.79 km) |
| Catonsville to Obertraubling | 4,204.38 mi (6,766.30 km) |
| Catonsville to Obertshausen | 4,036.65 mi (6,496.35 km) |
| Catonsville to Oberursel | 4,022.37 mi (6,473.38 km) |
| Catonsville to Ochsenfurt | 4,098.63 mi (6,596.10 km) |
| Catonsville to Ochsenhausen | 4,142.23 mi (6,666.27 km) |
| Catonsville to Ochtrup | 3,911.64 mi (6,295.17 km) |
| Catonsville to Odenthal | 3,940.51 mi (6,341.65 km) |
| Catonsville to Oelde | 3,959.27 mi (6,371.84 km) |
| Catonsville to Oelsnitz | 4,158.52 mi (6,692.50 km) |
| Catonsville to Oer-Erkenschwick | 3,929.20 mi (6,323.43 km) |
