| Big Spring to Orbetello | 5,745.53 mi (9,246.53 km) |
| Big Spring to Oria | 6,085.67 mi (9,793.95 km) |
| Big Spring to Oristano | 5,744.01 mi (9,244.08 km) |
| Big Spring to Orta Nova | 5,972.57 mi (9,611.92 km) |
| Big Spring to Orte | 5,791.42 mi (9,320.38 km) |
| Big Spring to Ortona | 5,875.48 mi (9,455.68 km) |
| Big Spring to Orvieto | 5,769.31 mi (9,284.81 km) |
| Big Spring to Orzinuovi | 5,570.22 mi (8,964.40 km) |
| Big Spring to Osimo | 5,789.69 mi (9,317.61 km) |
| Big Spring to Ospitaletto | 5,569.16 mi (8,962.70 km) |
| Big Spring to Ostuni | 6,072.89 mi (9,773.36 km) |
| Big Spring to Ottaviano | 5,945.52 mi (9,568.40 km) |
| Big Spring to Ovada | 5,551.23 mi (8,933.84 km) |
| Big Spring to Ozieri | 5,733.16 mi (9,226.63 km) |
| Big Spring to Paceco | 5,993.33 mi (9,645.33 km) |
