| Calhoun to Orbetello | 4,941.64 mi (7,952.80 km) |
| Calhoun to Oria | 5,294.17 mi (8,520.15 km) |
| Calhoun to Oristano | 4,910.72 mi (7,903.04 km) |
| Calhoun to Orta Nova | 5,178.83 mi (8,334.52 km) |
| Calhoun to Orte | 4,992.43 mi (8,034.54 km) |
| Calhoun to Ortona | 5,084.06 mi (8,182.00 km) |
| Calhoun to Orvieto | 4,971.26 mi (8,000.47 km) |
| Calhoun to Orzinuovi | 4,785.72 mi (7,701.87 km) |
| Calhoun to Osimo | 5,003.51 mi (8,052.37 km) |
| Calhoun to Ospitaletto | 4,786.53 mi (7,703.18 km) |
| Calhoun to Ostuni | 5,282.95 mi (8,502.08 km) |
| Calhoun to Ottaviano | 5,142.71 mi (8,276.40 km) |
| Calhoun to Ovada | 4,755.35 mi (7,652.99 km) |
| Calhoun to Ozieri | 4,906.44 mi (7,896.14 km) |
| Calhoun to Paceco | 5,161.41 mi (8,306.49 km) |
