| Rancho San Diego to Orbetello | 6,289.76 mi (10,122.39 km) |
| Rancho San Diego to Oria | 6,603.64 mi (10,627.52 km) |
| Rancho San Diego to Oristano | 6,327.40 mi (10,182.97 km) |
| Rancho San Diego to Orta Nova | 6,496.88 mi (10,455.71 km) |
| Rancho San Diego to Orte | 6,327.93 mi (10,183.83 km) |
| Rancho San Diego to Ortona | 6,399.70 mi (10,299.33 km) |
| Rancho San Diego to Orvieto | 6,305.27 mi (10,147.35 km) |
| Rancho San Diego to Orzinuovi | 6,094.93 mi (9,808.84 km) |
| Rancho San Diego to Osimo | 6,309.78 mi (10,154.62 km) |
| Rancho San Diego to Ospitaletto | 6,091.55 mi (9,803.41 km) |
| Rancho San Diego to Ostuni | 6,589.19 mi (10,604.27 km) |
| Rancho San Diego to Ottaviano | 6,482.54 mi (10,432.63 km) |
| Rancho San Diego to Ovada | 6,090.86 mi (9,802.30 km) |
| Rancho San Diego to Ozieri | 6,307.96 mi (10,151.68 km) |
| Rancho San Diego to Paceco | 6,568.34 mi (10,570.72 km) |
