| Rio Maior to Oberkirch | 1,054.79 mi (1,697.52 km) |
| Rio Maior to Obernburg am Main | 1,142.85 mi (1,839.24 km) |
| Rio Maior to Obernkirchen | 1,240.12 mi (1,995.79 km) |
| Rio Maior to Oberschleissheim | 1,188.14 mi (1,912.12 km) |
| Rio Maior to Oberstdorf | 1,110.28 mi (1,786.82 km) |
| Rio Maior to Obertraubling | 1,233.41 mi (1,984.98 km) |
| Rio Maior to Obertshausen | 1,139.96 mi (1,834.58 km) |
| Rio Maior to Oberursel | 1,135.88 mi (1,828.02 km) |
| Rio Maior to Ochsenfurt | 1,171.27 mi (1,884.98 km) |
| Rio Maior to Ochsenhausen | 1,115.23 mi (1,794.79 km) |
| Rio Maior to Ochtrup | 1,175.68 mi (1,892.08 km) |
| Rio Maior to Odenthal | 1,119.75 mi (1,802.06 km) |
| Rio Maior to Oelde | 1,189.35 mi (1,914.08 km) |
| Rio Maior to Oelsnitz | 1,278.47 mi (2,057.50 km) |
| Rio Maior to Oer-Erkenschwick | 1,151.54 mi (1,853.22 km) |
