| Ridge to Nuth | 3,665.32 mi (5,898.76 km) |
| Ridge to Oegstgeest | 3,577.09 mi (5,756.76 km) |
| Ridge to Oirschot | 3,627.03 mi (5,837.14 km) |
| Ridge to Oisterwijk | 3,620.95 mi (5,827.35 km) |
| Ridge to Oldebroek | 3,627.33 mi (5,837.62 km) |
| Ridge to Oldenzaal | 3,671.28 mi (5,908.36 km) |
| Ridge to Ommen | 3,645.97 mi (5,867.63 km) |
| Ridge to Oosterend | 3,620.31 mi (5,826.33 km) |
| Ridge to Oosterhout | 3,605.72 mi (5,802.85 km) |
| Ridge to Oosterwolde | 3,629.39 mi (5,840.94 km) |
| Ridge to Oostzaan | 3,587.64 mi (5,773.75 km) |
| Ridge to Opmeer | 3,583.92 mi (5,767.76 km) |
| Ridge to Oss | 3,629.05 mi (5,840.39 km) |
| Ridge to Oud-Beijerland | 3,583.20 mi (5,766.60 km) |
| Ridge to Oudenbosch | 3,593.68 mi (5,783.47 km) |
