| Willoughby to Oskaloosa (Iowa) | 581.61 mi (936.01 km) |
| Willoughby to Oswego (Illinois) | 357.55 mi (575.42 km) |
| Willoughby to Oswego (New York) | 279.18 mi (449.29 km) |
| Willoughby to Otsego (Minnesota) | 660.73 mi (1,063.34 km) |
| Willoughby to Ottawa (Illinois) | 384.25 mi (618.39 km) |
| Willoughby to Ottawa (Kansas) | 760.70 mi (1,224.23 km) |
| Willoughby to Ottumwa (Iowa) | 572.47 mi (921.30 km) |
| Willoughby to Overland (Missouri) | 514.76 mi (828.43 km) |
| Willoughby to Overland Park (Kansas) | 724.72 mi (1,166.32 km) |
| Willoughby to Overlea (Maryland) | 301.38 mi (485.02 km) |
| Willoughby to Oviedo (Florida) | 897.46 mi (1,444.33 km) |
| Willoughby to Owasso (Oklahoma) | 857.21 mi (1,379.55 km) |
| Willoughby to Owatonna (Minnesota) | 621.45 mi (1,000.13 km) |
| Willoughby to Owensboro (Kentucky) | 405.14 mi (652.01 km) |
| Willoughby to Owings Mills (Maryland) | 287.39 mi (462.50 km) |
