| Mercer Island to Oerlinghausen | 4,974.16 mi (8,005.14 km) |
| Mercer Island to Oestrich-Winkel | 5,073.24 mi (8,164.59 km) |
| Mercer Island to Offenburg | 5,161.06 mi (8,305.93 km) |
| Mercer Island to Oftersheim | 5,123.96 mi (8,246.22 km) |
| Mercer Island to Ohrdruf | 5,087.89 mi (8,188.16 km) |
| Mercer Island to Ohringen | 5,155.70 mi (8,297.30 km) |
| Mercer Island to Olbernhau | 5,154.64 mi (8,295.59 km) |
| Mercer Island to Olching | 5,257.51 mi (8,461.14 km) |
| Mercer Island to Oldenburg | 4,895.43 mi (7,878.43 km) |
| Mercer Island to Oldenburg in Holstein | 4,885.98 mi (7,863.23 km) |
| Mercer Island to Olfen | 4,959.00 mi (7,980.74 km) |
| Mercer Island to Olpe | 5,010.14 mi (8,063.04 km) |
| Mercer Island to Olsberg | 5,005.91 mi (8,056.23 km) |
| Mercer Island to Oranienburg | 5,027.08 mi (8,090.30 km) |
| Mercer Island to Ortenberg | 5,077.34 mi (8,171.18 km) |
