| Cascais to Oberkirch | 1,103.65 mi (1,776.15 km) |
| Cascais to Obernburg am Main | 1,192.31 mi (1,918.84 km) |
| Cascais to Obernkirchen | 1,290.62 mi (2,077.05 km) |
| Cascais to Oberschleissheim | 1,235.69 mi (1,988.64 km) |
| Cascais to Oberstdorf | 1,157.36 mi (1,862.58 km) |
| Cascais to Obertraubling | 1,281.44 mi (2,062.28 km) |
| Cascais to Obertshausen | 1,189.62 mi (1,914.51 km) |
| Cascais to Oberursel | 1,185.68 mi (1,908.16 km) |
| Cascais to Ochsenfurt | 1,220.37 mi (1,964.00 km) |
| Cascais to Ochsenhausen | 1,163.09 mi (1,871.82 km) |
| Cascais to Ochtrup | 1,226.39 mi (1,973.68 km) |
| Cascais to Odenthal | 1,170.18 mi (1,883.23 km) |
| Cascais to Oelde | 1,239.86 mi (1,995.36 km) |
| Cascais to Oelsnitz | 1,327.57 mi (2,136.51 km) |
| Cascais to Oer-Erkenschwick | 1,202.12 mi (1,934.62 km) |
