| Helena to Oberkirch | 4,944.76 mi (7,957.82 km) |
| Helena to Obernburg am Main | 4,904.06 mi (7,892.32 km) |
| Helena to Obernkirchen | 4,772.65 mi (7,680.84 km) |
| Helena to Oberschleissheim | 5,058.10 mi (8,140.22 km) |
| Helena to Oberstdorf | 5,068.50 mi (8,156.96 km) |
| Helena to Obertraubling | 5,034.75 mi (8,102.65 km) |
| Helena to Obertshausen | 4,883.28 mi (7,858.87 km) |
| Helena to Oberursel | 4,868.81 mi (7,835.59 km) |
| Helena to Ochsenfurt | 4,939.91 mi (7,950.02 km) |
| Helena to Ochsenhausen | 5,022.81 mi (8,083.43 km) |
| Helena to Ochtrup | 4,723.90 mi (7,602.38 km) |
| Helena to Odenthal | 4,783.86 mi (7,698.88 km) |
| Helena to Oelde | 4,769.79 mi (7,676.24 km) |
| Helena to Oelsnitz | 4,954.30 mi (7,973.17 km) |
| Helena to Oer-Erkenschwick | 4,755.34 mi (7,652.98 km) |
