| Round Rock to Nuth | 5,148.15 mi (8,285.15 km) |
| Round Rock to Oegstgeest | 5,052.49 mi (8,131.19 km) |
| Round Rock to Oirschot | 5,106.37 mi (8,217.91 km) |
| Round Rock to Oisterwijk | 5,099.82 mi (8,207.37 km) |
| Round Rock to Oldebroek | 5,096.64 mi (8,202.25 km) |
| Round Rock to Oldenzaal | 5,139.06 mi (8,270.52 km) |
| Round Rock to Ommen | 5,113.30 mi (8,229.07 km) |
| Round Rock to Oosterend | 5,084.01 mi (8,181.92 km) |
| Round Rock to Oosterhout | 5,084.94 mi (8,183.41 km) |
| Round Rock to Oosterwolde | 5,092.61 mi (8,195.77 km) |
| Round Rock to Oostzaan | 5,059.72 mi (8,142.84 km) |
| Round Rock to Opmeer | 5,053.37 mi (8,132.62 km) |
| Round Rock to Oss | 5,105.51 mi (8,216.53 km) |
| Round Rock to Oud-Beijerland | 5,062.03 mi (8,146.55 km) |
| Round Rock to Oudenbosch | 5,074.19 mi (8,166.11 km) |
