| Philadelphia to Oskaloosa (Iowa) | 920.42 mi (1,481.27 km) |
| Philadelphia to Oswego (Illinois) | 699.02 mi (1,124.97 km) |
| Philadelphia to Oswego (New York) | 248.15 mi (399.37 km) |
| Philadelphia to Otsego (Minnesota) | 1,004.59 mi (1,616.73 km) |
| Philadelphia to Ottawa (Illinois) | 722.67 mi (1,163.02 km) |
| Philadelphia to Ottawa (Kansas) | 1,078.30 mi (1,735.36 km) |
| Philadelphia to Ottumwa (Iowa) | 909.13 mi (1,463.10 km) |
| Philadelphia to Overland (Missouri) | 817.98 mi (1,316.40 km) |
| Philadelphia to Overland Park (Kansas) | 1,044.01 mi (1,680.18 km) |
| Philadelphia to Overlea (Maryland) | 85.96 mi (138.34 km) |
| Philadelphia to Oviedo (Florida) | 856.31 mi (1,378.09 km) |
| Philadelphia to Owasso (Oklahoma) | 1,150.77 mi (1,851.98 km) |
| Philadelphia to Owatonna (Minnesota) | 968.11 mi (1,558.03 km) |
| Philadelphia to Owensboro (Kentucky) | 662.43 mi (1,066.08 km) |
| Philadelphia to Owings Mills (Maryland) | 97.25 mi (156.51 km) |
