| Hopatcong to Oerlinghausen | 3,815.71 mi (6,140.79 km) |
| Hopatcong to Oestrich-Winkel | 3,845.59 mi (6,188.87 km) |
| Hopatcong to Offenburg | 3,888.20 mi (6,257.45 km) |
| Hopatcong to Oftersheim | 3,887.77 mi (6,256.77 km) |
| Hopatcong to Ohrdruf | 3,929.68 mi (6,324.21 km) |
| Hopatcong to Ohringen | 3,930.03 mi (6,324.77 km) |
| Hopatcong to Olbernhau | 4,036.18 mi (6,495.60 km) |
| Hopatcong to Olching | 4,035.21 mi (6,494.05 km) |
| Hopatcong to Oldenburg | 3,765.80 mi (6,060.47 km) |
| Hopatcong to Oldenburg in Holstein | 3,834.06 mi (6,170.33 km) |
| Hopatcong to Olfen | 3,772.51 mi (6,071.26 km) |
| Hopatcong to Olpe | 3,809.77 mi (6,131.24 km) |
| Hopatcong to Olsberg | 3,825.99 mi (6,157.34 km) |
| Hopatcong to Oranienburg | 3,966.98 mi (6,384.23 km) |
| Hopatcong to Ortenberg | 3,877.46 mi (6,240.17 km) |
