| Iowa City to Oberkirch | 4,522.41 mi (7,278.12 km) |
| Iowa City to Obernburg am Main | 4,508.03 mi (7,254.98 km) |
| Iowa City to Obernkirchen | 4,409.66 mi (7,096.67 km) |
| Iowa City to Oberschleissheim | 4,661.87 mi (7,502.55 km) |
| Iowa City to Oberstdorf | 4,650.24 mi (7,483.84 km) |
| Iowa City to Obertraubling | 4,652.95 mi (7,488.20 km) |
| Iowa City to Obertshausen | 4,487.75 mi (7,222.34 km) |
| Iowa City to Oberursel | 4,473.02 mi (7,198.63 km) |
| Iowa City to Ochsenfurt | 4,549.08 mi (7,321.04 km) |
| Iowa City to Ochsenhausen | 4,610.24 mi (7,419.46 km) |
| Iowa City to Ochtrup | 4,344.84 mi (6,992.34 km) |
| Iowa City to Odenthal | 4,387.70 mi (7,061.32 km) |
| Iowa City to Oelde | 4,393.04 mi (7,069.92 km) |
| Iowa City to Oelsnitz | 4,591.38 mi (7,389.11 km) |
| Iowa City to Oer-Erkenschwick | 4,368.78 mi (7,030.87 km) |
