| Downers Grove to Oerlinghausen | 4,274.77 mi (6,879.58 km) |
| Downers Grove to Oestrich-Winkel | 4,324.76 mi (6,960.03 km) |
| Downers Grove to Offenburg | 4,381.00 mi (7,050.54 km) |
| Downers Grove to Oftersheim | 4,370.62 mi (7,033.84 km) |
| Downers Grove to Ohrdruf | 4,392.53 mi (7,069.09 km) |
| Downers Grove to Ohringen | 4,411.35 mi (7,099.38 km) |
| Downers Grove to Olbernhau | 4,491.62 mi (7,228.56 km) |
| Downers Grove to Olching | 4,518.88 mi (7,272.44 km) |
| Downers Grove to Oldenburg | 4,215.04 mi (6,783.45 km) |
| Downers Grove to Oldenburg in Holstein | 4,263.83 mi (6,861.98 km) |
| Downers Grove to Olfen | 4,237.89 mi (6,820.23 km) |
| Downers Grove to Olpe | 4,280.27 mi (6,888.43 km) |
| Downers Grove to Olsberg | 4,291.37 mi (6,906.29 km) |
| Downers Grove to Oranienburg | 4,403.86 mi (7,087.33 km) |
| Downers Grove to Ortenberg | 4,350.05 mi (7,000.73 km) |
