| Philadelphia to Olympia (Washington) | 2,402.87 mi (3,867.04 km) |
| Philadelphia to Olympia Heights (Florida) | 1,031.57 mi (1,660.16 km) |
| Philadelphia to Omaha (Nebraska) | 1,097.60 mi (1,766.42 km) |
| Philadelphia to On Top of the World Designated Place (Florida) | 855.43 mi (1,376.68 km) |
| Philadelphia to Onalaska (Wisconsin) | 866.75 mi (1,394.90 km) |
| Philadelphia to Oneida (New York) | 213.81 mi (344.10 km) |
| Philadelphia to Oneonta (New York) | 169.14 mi (272.20 km) |
| Philadelphia to Ontario (California) | 2,356.29 mi (3,792.08 km) |
| Philadelphia to Ontario (Oregon) | 2,142.45 mi (3,447.94 km) |
| Philadelphia to Opa-locka (Florida) | 1,018.48 mi (1,639.09 km) |
| Philadelphia to Opelika (Alabama) | 762.38 mi (1,226.92 km) |
| Philadelphia to Opelousas (Louisiana) | 1,155.80 mi (1,860.08 km) |
| Philadelphia to Orange (California) | 2,373.99 mi (3,820.57 km) |
| Philadelphia to Orange (Texas) | 1,251.42 mi (2,013.96 km) |
| Philadelphia to Orange City (Florida) | 840.98 mi (1,353.42 km) |
