| Sioux City to Orbetello | 5,048.23 mi (8,124.34 km) |
| Sioux City to Oria | 5,378.91 mi (8,656.51 km) |
| Sioux City to Oristano | 5,065.36 mi (8,151.91 km) |
| Sioux City to Orta Nova | 5,267.85 mi (8,477.78 km) |
| Sioux City to Orte | 5,090.98 mi (8,193.15 km) |
| Sioux City to Ortona | 5,170.33 mi (8,320.84 km) |
| Sioux City to Orvieto | 5,068.55 mi (8,157.05 km) |
| Sioux City to Orzinuovi | 4,864.00 mi (7,827.85 km) |
| Sioux City to Osimo | 5,082.54 mi (8,179.56 km) |
| Sioux City to Ospitaletto | 4,862.01 mi (7,824.64 km) |
| Sioux City to Ostuni | 5,365.42 mi (8,634.81 km) |
| Sioux City to Ottaviano | 5,245.93 mi (8,442.51 km) |
| Sioux City to Ovada | 4,851.14 mi (7,807.16 km) |
| Sioux City to Ozieri | 5,050.11 mi (8,127.37 km) |
| Sioux City to Paceco | 5,311.38 mi (8,547.84 km) |
