| Havre de Grace to Oerlinghausen | 3,937.89 mi (6,337.42 km) |
| Havre de Grace to Oestrich-Winkel | 3,966.84 mi (6,384.01 km) |
| Havre de Grace to Offenburg | 4,008.66 mi (6,451.32 km) |
| Havre de Grace to Oftersheim | 4,008.81 mi (6,451.55 km) |
| Havre de Grace to Ohrdruf | 4,051.65 mi (6,520.50 km) |
| Havre de Grace to Ohringen | 4,051.12 mi (6,519.65 km) |
| Havre de Grace to Olbernhau | 4,158.40 mi (6,692.29 km) |
| Havre de Grace to Olching | 4,156.12 mi (6,688.63 km) |
| Havre de Grace to Oldenburg | 3,888.36 mi (6,257.71 km) |
| Havre de Grace to Oldenburg in Holstein | 3,957.17 mi (6,368.45 km) |
| Havre de Grace to Olfen | 3,894.45 mi (6,267.51 km) |
| Havre de Grace to Olpe | 3,931.47 mi (6,327.09 km) |
| Havre de Grace to Olsberg | 3,947.91 mi (6,353.54 km) |
| Havre de Grace to Oranienburg | 4,089.85 mi (6,581.98 km) |
| Havre de Grace to Ortenberg | 3,999.02 mi (6,435.80 km) |
