| Piqua to Oberkirch | 4,314.44 mi (6,943.42 km) |
| Piqua to Obernburg am Main | 4,309.73 mi (6,935.84 km) |
| Piqua to Obernkirchen | 4,225.06 mi (6,799.58 km) |
| Piqua to Oberschleissheim | 4,460.83 mi (7,179.02 km) |
| Piqua to Oberstdorf | 4,441.58 mi (7,148.03 km) |
| Piqua to Obertraubling | 4,457.22 mi (7,173.20 km) |
| Piqua to Obertshausen | 4,289.99 mi (6,904.07 km) |
| Piqua to Oberursel | 4,275.43 mi (6,880.64 km) |
| Piqua to Ochsenfurt | 4,351.93 mi (7,003.75 km) |
| Piqua to Ochsenhausen | 4,404.27 mi (7,087.98 km) |
| Piqua to Ochtrup | 4,155.63 mi (6,687.84 km) |
| Piqua to Odenthal | 4,191.51 mi (6,745.58 km) |
| Piqua to Oelde | 4,203.77 mi (6,765.31 km) |
| Piqua to Oelsnitz | 4,403.48 mi (7,086.72 km) |
| Piqua to Oer-Erkenschwick | 4,176.41 mi (6,721.28 km) |
