| Duncan to Oberkirch | 5,117.67 mi (8,236.10 km) |
| Duncan to Obernburg am Main | 5,105.46 mi (8,216.44 km) |
| Duncan to Obernkirchen | 5,009.30 mi (8,061.70 km) |
| Duncan to Oberschleissheim | 5,258.84 mi (8,463.29 km) |
| Duncan to Oberstdorf | 5,245.44 mi (8,441.71 km) |
| Duncan to Obertraubling | 5,250.97 mi (8,450.62 km) |
| Duncan to Obertshausen | 5,085.27 mi (8,183.95 km) |
| Duncan to Oberursel | 5,070.56 mi (8,160.28 km) |
| Duncan to Ochsenfurt | 5,146.76 mi (8,282.91 km) |
| Duncan to Ochsenhausen | 5,206.06 mi (8,378.35 km) |
| Duncan to Ochtrup | 4,943.77 mi (7,956.23 km) |
| Duncan to Odenthal | 4,985.45 mi (8,023.30 km) |
| Duncan to Oelde | 4,991.99 mi (8,033.84 km) |
| Duncan to Oelsnitz | 5,190.66 mi (8,353.57 km) |
| Duncan to Oer-Erkenschwick | 4,967.21 mi (7,993.95 km) |
