| Chicago to Opwijk | 4,132.71 mi (6,650.95 km) |
| Chicago to Ostend | 4,076.28 mi (6,560.13 km) |
| Chicago to Oud-Heverlee | 4,155.52 mi (6,687.67 km) |
| Chicago to Oud-Turnhout | 4,150.20 mi (6,679.10 km) |
| Chicago to Oudenaarde | 4,114.86 mi (6,622.22 km) |
| Chicago to Oudenburg | 4,080.76 mi (6,567.35 km) |
| Chicago to Oupeye | 4,196.49 mi (6,753.61 km) |
| Chicago to Overijse | 4,152.29 mi (6,682.47 km) |
| Chicago to Overpelt | 4,169.82 mi (6,710.68 km) |
| Chicago to Paal | 4,167.10 mi (6,706.30 km) |
| Chicago to Peer | 4,174.19 mi (6,717.70 km) |
| Chicago to Pepinster | 4,208.10 mi (6,772.28 km) |
| Chicago to Peruwelz | 4,125.85 mi (6,639.91 km) |
| Chicago to Perwez | 4,168.52 mi (6,708.59 km) |
| Chicago to Philippeville | 4,173.66 mi (6,716.86 km) |
