| Owings Mills to Nuth | 3,889.58 mi (6,259.67 km) |
| Owings Mills to Oegstgeest | 3,800.30 mi (6,115.99 km) |
| Owings Mills to Oirschot | 3,850.81 mi (6,197.27 km) |
| Owings Mills to Oisterwijk | 3,844.66 mi (6,187.38 km) |
| Owings Mills to Oldebroek | 3,849.81 mi (6,195.67 km) |
| Owings Mills to Oldenzaal | 3,893.62 mi (6,266.17 km) |
| Owings Mills to Ommen | 3,868.22 mi (6,225.29 km) |
| Owings Mills to Oosterend | 3,842.04 mi (6,183.17 km) |
| Owings Mills to Oosterhout | 3,829.46 mi (6,162.92 km) |
| Owings Mills to Oosterwolde | 3,851.07 mi (6,197.70 km) |
| Owings Mills to Oostzaan | 3,810.43 mi (6,132.30 km) |
| Owings Mills to Opmeer | 3,806.36 mi (6,125.75 km) |
| Owings Mills to Oss | 3,852.46 mi (6,199.94 km) |
| Owings Mills to Oud-Beijerland | 3,806.86 mi (6,126.55 km) |
| Owings Mills to Oudenbosch | 3,817.57 mi (6,143.78 km) |
