| Des Plaines to Orbetello | 4,739.19 mi (7,626.99 km) |
| Des Plaines to Oria | 5,080.07 mi (8,175.59 km) |
| Des Plaines to Oristano | 4,738.73 mi (7,626.24 km) |
| Des Plaines to Orta Nova | 4,966.75 mi (7,993.21 km) |
| Des Plaines to Orte | 4,785.24 mi (7,701.10 km) |
| Des Plaines to Ortona | 4,869.75 mi (7,837.11 km) |
| Des Plaines to Orvieto | 4,763.16 mi (7,665.57 km) |
| Des Plaines to Orzinuovi | 4,564.77 mi (7,346.29 km) |
| Des Plaines to Osimo | 4,784.29 mi (7,699.56 km) |
| Des Plaines to Ospitaletto | 4,563.87 mi (7,344.83 km) |
| Des Plaines to Ostuni | 5,067.39 mi (8,155.18 km) |
| Des Plaines to Ottaviano | 4,939.27 mi (7,948.98 km) |
| Des Plaines to Ovada | 4,545.08 mi (7,314.60 km) |
| Des Plaines to Ozieri | 4,727.34 mi (7,607.93 km) |
| Des Plaines to Paceco | 4,987.73 mi (8,026.98 km) |
