| Rockford to Oberkirch | 4,401.79 mi (7,083.99 km) |
| Rockford to Obernburg am Main | 4,389.07 mi (7,063.53 km) |
| Rockford to Obernkirchen | 4,293.11 mi (6,909.10 km) |
| Rockford to Oberschleissheim | 4,542.52 mi (7,310.49 km) |
| Rockford to Oberstdorf | 4,529.58 mi (7,289.65 km) |
| Rockford to Obertraubling | 4,534.54 mi (7,297.64 km) |
| Rockford to Obertshausen | 4,368.87 mi (7,031.02 km) |
| Rockford to Oberursel | 4,354.16 mi (7,007.35 km) |
| Rockford to Ochsenfurt | 4,430.35 mi (7,129.96 km) |
| Rockford to Ochsenhausen | 4,490.01 mi (7,225.97 km) |
| Rockford to Ochtrup | 4,227.39 mi (6,803.33 km) |
| Rockford to Odenthal | 4,269.03 mi (6,870.34 km) |
| Rockford to Oelde | 4,275.62 mi (6,880.95 km) |
| Rockford to Oelsnitz | 4,474.35 mi (7,200.78 km) |
| Rockford to Oer-Erkenschwick | 4,250.78 mi (6,840.97 km) |
