| Oak Forest to Oerlinghausen | 4,274.73 mi (6,879.51 km) |
| Oak Forest to Oestrich-Winkel | 4,324.02 mi (6,958.83 km) |
| Oak Forest to Offenburg | 4,379.77 mi (7,048.56 km) |
| Oak Forest to Oftersheim | 4,369.76 mi (7,032.45 km) |
| Oak Forest to Ohrdruf | 4,392.40 mi (7,068.88 km) |
| Oak Forest to Ohringen | 4,410.56 mi (7,098.11 km) |
| Oak Forest to Olbernhau | 4,491.79 mi (7,228.83 km) |
| Oak Forest to Olching | 4,518.04 mi (7,271.09 km) |
| Oak Forest to Oldenburg | 4,215.31 mi (6,783.89 km) |
| Oak Forest to Oldenburg in Holstein | 4,264.79 mi (6,863.52 km) |
| Oak Forest to Olfen | 4,237.61 mi (6,819.78 km) |
| Oak Forest to Olpe | 4,279.82 mi (6,887.70 km) |
| Oak Forest to Olsberg | 4,291.11 mi (6,905.87 km) |
| Oak Forest to Oranienburg | 4,404.64 mi (7,088.58 km) |
| Oak Forest to Ortenberg | 4,349.55 mi (6,999.93 km) |
