| Wilmette to Oerlinghausen | 4,250.43 mi (6,840.41 km) |
| Wilmette to Oestrich-Winkel | 4,300.54 mi (6,921.05 km) |
| Wilmette to Offenburg | 4,356.88 mi (7,011.73 km) |
| Wilmette to Oftersheim | 4,346.43 mi (6,994.90 km) |
| Wilmette to Ohrdruf | 4,368.20 mi (7,029.94 km) |
| Wilmette to Ohringen | 4,387.14 mi (7,060.42 km) |
| Wilmette to Olbernhau | 4,467.25 mi (7,189.34 km) |
| Wilmette to Olching | 4,494.68 mi (7,233.49 km) |
| Wilmette to Oldenburg | 4,190.65 mi (6,744.20 km) |
| Wilmette to Oldenburg in Holstein | 4,239.37 mi (6,822.61 km) |
| Wilmette to Olfen | 4,213.59 mi (6,781.12 km) |
| Wilmette to Olpe | 4,255.99 mi (6,849.36 km) |
| Wilmette to Olsberg | 4,267.06 mi (6,867.18 km) |
| Wilmette to Oranienburg | 4,379.42 mi (7,047.99 km) |
| Wilmette to Ortenberg | 4,325.78 mi (6,961.68 km) |
