| Philadelphia to Orbetello | 4,282.09 mi (6,891.35 km) |
| Philadelphia to Oria | 4,634.95 mi (7,459.24 km) |
| Philadelphia to Oristano | 4,251.54 mi (6,842.19 km) |
| Philadelphia to Orta Nova | 4,519.56 mi (7,273.53 km) |
| Philadelphia to Orte | 4,333.02 mi (6,973.33 km) |
| Philadelphia to Ortona | 4,424.96 mi (7,121.28 km) |
| Philadelphia to Orvieto | 4,311.90 mi (6,939.33 km) |
| Philadelphia to Orzinuovi | 4,127.29 mi (6,642.23 km) |
| Philadelphia to Osimo | 4,344.78 mi (6,992.25 km) |
| Philadelphia to Ospitaletto | 4,128.25 mi (6,643.78 km) |
| Philadelphia to Ostuni | 4,623.81 mi (7,441.30 km) |
| Philadelphia to Ottaviano | 4,483.14 mi (7,214.91 km) |
| Philadelphia to Ovada | 4,096.20 mi (6,592.19 km) |
| Philadelphia to Ozieri | 4,246.95 mi (6,834.80 km) |
| Philadelphia to Paceco | 4,502.26 mi (7,245.69 km) |
