| Round Rock to Oberkirch | 5,316.66 mi (8,556.34 km) |
| Round Rock to Obernburg am Main | 5,309.51 mi (8,544.84 km) |
| Round Rock to Obernkirchen | 5,220.11 mi (8,400.96 km) |
| Round Rock to Oberschleissheim | 5,461.51 mi (8,789.45 km) |
| Round Rock to Oberstdorf | 5,444.04 mi (8,761.33 km) |
| Round Rock to Obertraubling | 5,456.38 mi (8,781.19 km) |
| Round Rock to Obertshausen | 5,289.60 mi (8,512.79 km) |
| Round Rock to Oberursel | 5,274.97 mi (8,489.25 km) |
| Round Rock to Ochsenfurt | 5,351.42 mi (8,612.27 km) |
| Round Rock to Ochsenhausen | 5,406.11 mi (8,700.30 km) |
| Round Rock to Ochtrup | 5,152.32 mi (8,291.85 km) |
| Round Rock to Odenthal | 5,190.55 mi (8,353.38 km) |
| Round Rock to Oelde | 5,200.54 mi (8,369.45 km) |
| Round Rock to Oelsnitz | 5,399.97 mi (8,690.42 km) |
| Round Rock to Oer-Erkenschwick | 5,174.21 mi (8,327.09 km) |
