| Mercer Island to Oberkirch | 5,160.84 mi (8,305.57 km) |
| Mercer Island to Obernburg am Main | 5,109.62 mi (8,223.14 km) |
| Mercer Island to Obernkirchen | 4,966.89 mi (7,993.44 km) |
| Mercer Island to Oberschleissheim | 5,260.31 mi (8,465.65 km) |
| Mercer Island to Oberstdorf | 5,280.10 mi (8,497.50 km) |
| Mercer Island to Obertraubling | 5,231.16 mi (8,418.74 km) |
| Mercer Island to Obertshausen | 5,089.08 mi (8,190.09 km) |
| Mercer Island to Oberursel | 5,075.05 mi (8,167.51 km) |
| Mercer Island to Ochsenfurt | 5,142.40 mi (8,275.89 km) |
| Mercer Island to Ochsenhausen | 5,232.93 mi (8,421.58 km) |
| Mercer Island to Ochtrup | 4,926.25 mi (7,928.03 km) |
| Mercer Island to Odenthal | 4,992.21 mi (8,034.19 km) |
| Mercer Island to Oelde | 4,970.07 mi (7,998.55 km) |
| Mercer Island to Oelsnitz | 5,144.28 mi (8,278.92 km) |
| Mercer Island to Oer-Erkenschwick | 4,960.20 mi (7,982.66 km) |
