| River Forest to Oberkirch | 4,371.94 mi (7,035.96 km) |
| River Forest to Obernburg am Main | 4,361.01 mi (7,018.36 km) |
| River Forest to Obernkirchen | 4,267.53 mi (6,867.93 km) |
| River Forest to Oberschleissheim | 4,514.01 mi (7,264.60 km) |
| River Forest to Oberstdorf | 4,499.65 mi (7,241.49 km) |
| River Forest to Obertraubling | 4,507.01 mi (7,253.33 km) |
| River Forest to Obertshausen | 4,340.90 mi (6,986.00 km) |
| River Forest to Oberursel | 4,326.22 mi (6,962.37 km) |
| River Forest to Ochsenfurt | 4,402.52 mi (7,085.16 km) |
| River Forest to Ochsenhausen | 4,460.57 mi (7,178.59 km) |
| River Forest to Ochtrup | 4,200.94 mi (6,760.76 km) |
| River Forest to Odenthal | 4,241.31 mi (6,825.72 km) |
| River Forest to Oelde | 4,249.18 mi (6,838.39 km) |
| River Forest to Oelsnitz | 4,448.24 mi (7,158.75 km) |
| River Forest to Oer-Erkenschwick | 4,223.75 mi (6,797.47 km) |
