| Walnut Creek to Orbetello | 6,156.89 mi (9,908.56 km) |
| Walnut Creek to Oria | 6,449.94 mi (10,380.17 km) |
| Walnut Creek to Oristano | 6,218.62 mi (10,007.90 km) |
| Walnut Creek to Orta Nova | 6,348.65 mi (10,217.17 km) |
| Walnut Creek to Orte | 6,189.76 mi (9,961.46 km) |
| Walnut Creek to Ortona | 6,252.99 mi (10,063.22 km) |
| Walnut Creek to Orvieto | 6,167.13 mi (9,925.03 km) |
| Walnut Creek to Orzinuovi | 5,953.44 mi (9,581.14 km) |
| Walnut Creek to Osimo | 6,162.08 mi (9,916.91 km) |
| Walnut Creek to Ospitaletto | 5,948.74 mi (9,573.58 km) |
| Walnut Creek to Ostuni | 6,434.75 mi (10,355.73 km) |
| Walnut Creek to Ottaviano | 6,342.17 mi (10,206.73 km) |
| Walnut Creek to Ovada | 5,958.42 mi (9,589.14 km) |
| Walnut Creek to Ozieri | 6,193.94 mi (9,968.18 km) |
| Walnut Creek to Paceco | 6,450.27 mi (10,380.71 km) |
