| Glen Ellyn to Oberkirch | 4,382.50 mi (7,052.95 km) |
| Glen Ellyn to Obernburg am Main | 4,371.36 mi (7,035.02 km) |
| Glen Ellyn to Obernkirchen | 4,277.59 mi (6,884.11 km) |
| Glen Ellyn to Oberschleissheim | 4,524.42 mi (7,281.35 km) |
| Glen Ellyn to Oberstdorf | 4,510.22 mi (7,258.50 km) |
| Glen Ellyn to Obertraubling | 4,517.30 mi (7,269.89 km) |
| Glen Ellyn to Obertshausen | 4,351.24 mi (7,002.64 km) |
| Glen Ellyn to Oberursel | 4,336.55 mi (6,979.00 km) |
| Glen Ellyn to Ochsenfurt | 4,412.84 mi (7,101.78 km) |
| Glen Ellyn to Ochsenhausen | 4,471.08 mi (7,195.51 km) |
| Glen Ellyn to Ochtrup | 4,211.10 mi (6,777.10 km) |
| Glen Ellyn to Odenthal | 4,251.61 mi (6,842.31 km) |
| Glen Ellyn to Oelde | 4,259.33 mi (6,854.73 km) |
| Glen Ellyn to Oelsnitz | 4,458.36 mi (7,175.04 km) |
| Glen Ellyn to Oer-Erkenschwick | 4,233.98 mi (6,813.93 km) |
