| Fountain Valley to Orbetello | 6,270.60 mi (10,091.55 km) |
| Fountain Valley to Oria | 6,580.64 mi (10,590.52 km) |
| Fountain Valley to Oristano | 6,313.04 mi (10,159.85 km) |
| Fountain Valley to Orta Nova | 6,474.87 mi (10,420.29 km) |
| Fountain Valley to Orte | 6,307.76 mi (10,151.36 km) |
| Fountain Valley to Ortona | 6,377.90 mi (10,264.24 km) |
| Fountain Valley to Orvieto | 6,285.08 mi (10,114.86 km) |
| Fountain Valley to Orzinuovi | 6,073.88 mi (9,774.96 km) |
| Fountain Valley to Osimo | 6,287.70 mi (10,119.08 km) |
| Fountain Valley to Ospitaletto | 6,070.23 mi (9,769.09 km) |
| Fountain Valley to Ostuni | 6,566.03 mi (10,567.01 km) |
| Fountain Valley to Ottaviano | 6,462.07 mi (10,399.70 km) |
| Fountain Valley to Ovada | 6,071.59 mi (9,771.28 km) |
| Fountain Valley to Ozieri | 6,292.54 mi (10,126.86 km) |
| Fountain Valley to Paceco | 6,552.38 mi (10,545.03 km) |
