| Houston to Oberkirch | 5,265.63 mi (8,474.21 km) |
| Houston to Obernburg am Main | 5,262.10 mi (8,468.53 km) |
| Houston to Obernkirchen | 5,177.86 mi (8,332.96 km) |
| Houston to Oberschleissheim | 5,412.86 mi (8,711.16 km) |
| Houston to Oberstdorf | 5,392.54 mi (8,678.46 km) |
| Houston to Obertraubling | 5,409.73 mi (8,706.11 km) |
| Houston to Obertshausen | 5,242.41 mi (8,436.85 km) |
| Houston to Oberursel | 5,227.87 mi (8,413.44 km) |
| Houston to Ochsenfurt | 5,304.37 mi (8,536.56 km) |
| Houston to Ochsenhausen | 5,355.69 mi (8,619.15 km) |
| Houston to Ochtrup | 5,108.46 mi (8,221.26 km) |
| Houston to Odenthal | 5,144.08 mi (8,278.59 km) |
| Houston to Oelde | 5,156.59 mi (8,298.73 km) |
| Houston to Oelsnitz | 5,356.31 mi (8,620.15 km) |
| Houston to Oer-Erkenschwick | 5,129.16 mi (8,254.59 km) |
