| Havre de Grace to Oberkirch | 4,012.90 mi (6,458.15 km) |
| Havre de Grace to Obernburg am Main | 4,017.56 mi (6,465.64 km) |
| Havre de Grace to Obernkirchen | 3,947.07 mi (6,352.19 km) |
| Havre de Grace to Oberschleissheim | 4,164.74 mi (6,702.50 km) |
| Havre de Grace to Oberstdorf | 4,138.34 mi (6,660.02 km) |
| Havre de Grace to Obertraubling | 4,166.26 mi (6,704.94 km) |
| Havre de Grace to Obertshausen | 3,998.52 mi (6,435.00 km) |
| Havre de Grace to Oberursel | 3,984.26 mi (6,412.04 km) |
| Havre de Grace to Ochsenfurt | 4,060.50 mi (6,534.74 km) |
| Havre de Grace to Ochsenhausen | 4,103.90 mi (6,604.59 km) |
| Havre de Grace to Ochtrup | 3,873.77 mi (6,234.22 km) |
| Havre de Grace to Odenthal | 3,902.46 mi (6,280.40 km) |
| Havre de Grace to Oelde | 3,921.38 mi (6,310.86 km) |
| Havre de Grace to Oelsnitz | 4,120.60 mi (6,631.46 km) |
| Havre de Grace to Oer-Erkenschwick | 3,891.24 mi (6,262.34 km) |
