| West Chicago to Oskaloosa (Iowa) | 231.89 mi (373.20 km) |
| West Chicago to Oswego (Illinois) | 15.78 mi (25.40 km) |
| West Chicago to Oswego (New York) | 604.69 mi (973.16 km) |
| West Chicago to Otsego (Minnesota) | 356.40 mi (573.57 km) |
| West Chicago to Ottawa (Illinois) | 48.55 mi (78.14 km) |
| West Chicago to Ottawa (Kansas) | 435.26 mi (700.48 km) |
| West Chicago to Ottumwa (Iowa) | 225.40 mi (362.74 km) |
| West Chicago to Overland (Missouri) | 248.23 mi (399.48 km) |
| West Chicago to Overland Park (Kansas) | 398.39 mi (641.15 km) |
| West Chicago to Overlea (Maryland) | 637.77 mi (1,026.39 km) |
| West Chicago to Oviedo (Florida) | 996.18 mi (1,603.19 km) |
| West Chicago to Owasso (Oklahoma) | 562.15 mi (904.69 km) |
| West Chicago to Owatonna (Minnesota) | 294.89 mi (474.57 km) |
| West Chicago to Owensboro (Kentucky) | 291.92 mi (469.80 km) |
| West Chicago to Owings Mills (Maryland) | 622.90 mi (1,002.46 km) |
