| Harper Woods to Oerlinghausen | 4,058.89 mi (6,532.15 km) |
| Harper Woods to Oestrich-Winkel | 4,103.24 mi (6,603.53 km) |
| Harper Woods to Offenburg | 4,155.77 mi (6,688.07 km) |
| Harper Woods to Oftersheim | 4,148.17 mi (6,675.83 km) |
| Harper Woods to Ohrdruf | 4,175.83 mi (6,720.35 km) |
| Harper Woods to Ohringen | 4,189.41 mi (6,742.21 km) |
| Harper Woods to Olbernhau | 4,277.30 mi (6,883.66 km) |
| Harper Woods to Olching | 4,296.51 mi (6,914.56 km) |
| Harper Woods to Oldenburg | 4,001.85 mi (6,440.36 km) |
| Harper Woods to Oldenburg in Holstein | 4,056.50 mi (6,528.31 km) |
| Harper Woods to Olfen | 4,020.10 mi (6,469.73 km) |
| Harper Woods to Olpe | 4,061.11 mi (6,535.73 km) |
| Harper Woods to Olsberg | 4,073.71 mi (6,556.00 km) |
| Harper Woods to Oranienburg | 4,194.79 mi (6,750.86 km) |
| Harper Woods to Ortenberg | 4,130.46 mi (6,647.33 km) |
