| Chicago to Oswego (Illinois) | 35.18 mi (56.62 km) |
| Chicago to Oswego (New York) | 578.87 mi (931.61 km) |
| Chicago to Otsego (Minnesota) | 379.82 mi (611.26 km) |
| Chicago to Ottawa (Illinois) | 67.64 mi (108.86 km) |
| Chicago to Ottawa (Kansas) | 457.84 mi (736.83 km) |
| Chicago to Ottumwa (Iowa) | 251.54 mi (404.81 km) |
| Chicago to Overland (Missouri) | 258.99 mi (416.80 km) |
| Chicago to Overland Park (Kansas) | 420.98 mi (677.49 km) |
| Chicago to Overlea (Maryland) | 609.82 mi (981.42 km) |
| Chicago to Oviedo (Florida) | 980.91 mi (1,578.62 km) |
| Chicago to Owasso (Oklahoma) | 580.84 mi (934.77 km) |
| Chicago to Owatonna (Minnesota) | 320.58 mi (515.93 km) |
| Chicago to Owensboro (Kentucky) | 283.51 mi (456.27 km) |
| Chicago to Owings Mills (Maryland) | 594.96 mi (957.50 km) |
| Chicago to Owosso (Michigan) | 196.11 mi (315.61 km) |
