| Portland to Oberkirch | 5,290.94 mi (8,514.94 km) |
| Portland to Obernburg am Main | 5,240.98 mi (8,434.54 km) |
| Portland to Obernkirchen | 5,099.45 mi (8,206.77 km) |
| Portland to Oberschleissheim | 5,392.16 mi (8,677.85 km) |
| Portland to Oberstdorf | 5,410.85 mi (8,707.92 km) |
| Portland to Obertraubling | 5,363.66 mi (8,631.97 km) |
| Portland to Obertshausen | 5,220.40 mi (8,401.42 km) |
| Portland to Oberursel | 5,206.30 mi (8,378.74 km) |
| Portland to Ochsenfurt | 5,274.14 mi (8,487.91 km) |
| Portland to Ochsenhausen | 5,363.82 mi (8,632.24 km) |
| Portland to Ochtrup | 5,057.85 mi (8,139.83 km) |
| Portland to Odenthal | 5,123.15 mi (8,244.91 km) |
| Portland to Oelde | 5,101.94 mi (8,210.79 km) |
| Portland to Oelsnitz | 5,277.42 mi (8,493.19 km) |
| Portland to Oer-Erkenschwick | 5,091.53 mi (8,194.02 km) |
