| Webster Groves to Orbetello | 4,990.56 mi (8,031.53 km) |
| Webster Groves to Oria | 5,334.18 mi (8,584.53 km) |
| Webster Groves to Oristano | 4,983.63 mi (8,020.37 km) |
| Webster Groves to Orta Nova | 5,220.32 mi (8,401.29 km) |
| Webster Groves to Orte | 5,037.61 mi (8,107.26 km) |
| Webster Groves to Ortona | 5,123.62 mi (8,245.66 km) |
| Webster Groves to Orvieto | 5,015.68 mi (8,071.96 km) |
| Webster Groves to Orzinuovi | 4,819.46 mi (7,756.17 km) |
| Webster Groves to Osimo | 5,038.96 mi (8,109.42 km) |
| Webster Groves to Ospitaletto | 4,818.87 mi (7,755.23 km) |
| Webster Groves to Ostuni | 5,321.75 mi (8,564.54 km) |
| Webster Groves to Ottaviano | 5,191.12 mi (8,354.30 km) |
| Webster Groves to Ovada | 4,797.71 mi (7,721.16 km) |
| Webster Groves to Ozieri | 4,973.80 mi (8,004.55 km) |
| Webster Groves to Paceco | 5,233.41 mi (8,422.37 km) |
