| Chicago to Opole | 4,637.67 mi (7,463.61 km) |
| Chicago to Orzesze | 4,688.10 mi (7,544.77 km) |
| Chicago to Osowa | 4,494.08 mi (7,232.52 km) |
| Chicago to Ostroda | 4,572.82 mi (7,359.25 km) |
| Chicago to Ostroleka | 4,651.50 mi (7,485.87 km) |
| Chicago to Ostrow Mazowiecka | 4,674.02 mi (7,522.11 km) |
| Chicago to Ostrow Wielkopolski | 4,591.31 mi (7,389.00 km) |
| Chicago to Ostrowiec Swietokrzyski | 4,742.06 mi (7,631.62 km) |
| Chicago to Ostrzeszow | 4,605.26 mi (7,411.44 km) |
| Chicago to Oswiecim | 4,709.12 mi (7,578.60 km) |
| Chicago to Otwock | 4,684.44 mi (7,538.88 km) |
| Chicago to Ozarow Mazowiecki | 4,664.88 mi (7,507.40 km) |
| Chicago to Ozimek | 4,646.93 mi (7,478.51 km) |
| Chicago to Ozorkow | 4,626.36 mi (7,445.41 km) |
| Chicago to Pabianice | 4,643.54 mi (7,473.05 km) |
