| Wilmette to Orbetello | 4,730.43 mi (7,612.89 km) |
| Wilmette to Oria | 5,071.41 mi (8,161.64 km) |
| Wilmette to Oristano | 4,729.79 mi (7,611.85 km) |
| Wilmette to Orta Nova | 4,958.06 mi (7,979.23 km) |
| Wilmette to Orte | 4,776.51 mi (7,687.05 km) |
| Wilmette to Ortona | 4,861.07 mi (7,823.14 km) |
| Wilmette to Orvieto | 4,754.44 mi (7,651.53 km) |
| Wilmette to Orzinuovi | 4,556.12 mi (7,332.37 km) |
| Wilmette to Osimo | 4,775.64 mi (7,685.64 km) |
| Wilmette to Ospitaletto | 4,555.23 mi (7,330.93 km) |
| Wilmette to Ostuni | 5,058.73 mi (8,141.25 km) |
| Wilmette to Ottaviano | 4,930.52 mi (7,934.90 km) |
| Wilmette to Ovada | 4,536.36 mi (7,300.56 km) |
| Wilmette to Ozieri | 4,718.44 mi (7,593.60 km) |
| Wilmette to Paceco | 4,978.81 mi (8,012.62 km) |
