| Piqua to Oskaloosa (Iowa) | 446.50 mi (718.58 km) |
| Piqua to Oswego (Illinois) | 238.47 mi (383.78 km) |
| Piqua to Oswego (New York) | 459.17 mi (738.97 km) |
| Piqua to Otsego (Minnesota) | 592.24 mi (953.13 km) |
| Piqua to Ottawa (Illinois) | 253.82 mi (408.49 km) |
| Piqua to Ottawa (Kansas) | 597.81 mi (962.09 km) |
| Piqua to Ottumwa (Iowa) | 432.95 mi (696.77 km) |
| Piqua to Overland (Missouri) | 341.90 mi (550.23 km) |
| Piqua to Overland Park (Kansas) | 563.07 mi (906.17 km) |
| Piqua to Overlea (Maryland) | 413.85 mi (666.03 km) |
| Piqua to Oviedo (Florida) | 812.81 mi (1,308.09 km) |
| Piqua to Owasso (Oklahoma) | 682.57 mi (1,098.49 km) |
| Piqua to Owatonna (Minnesota) | 534.58 mi (860.32 km) |
| Piqua to Owensboro (Kentucky) | 226.18 mi (364.01 km) |
| Piqua to Owings Mills (Maryland) | 398.89 mi (641.95 km) |
