| Gretna to Nuth | 4,884.72 mi (7,861.20 km) |
| Gretna to Oegstgeest | 4,794.21 mi (7,715.53 km) |
| Gretna to Oirschot | 4,845.40 mi (7,797.92 km) |
| Gretna to Oisterwijk | 4,839.17 mi (7,787.90 km) |
| Gretna to Oldebroek | 4,842.69 mi (7,793.56 km) |
| Gretna to Oldenzaal | 4,886.26 mi (7,863.68 km) |
| Gretna to Ommen | 4,860.75 mi (7,822.62 km) |
| Gretna to Oosterend | 4,833.84 mi (7,779.31 km) |
| Gretna to Oosterhout | 4,824.01 mi (7,763.50 km) |
| Gretna to Oosterwolde | 4,842.78 mi (7,793.70 km) |
| Gretna to Oostzaan | 4,803.78 mi (7,730.93 km) |
| Gretna to Opmeer | 4,799.22 mi (7,723.60 km) |
| Gretna to Oss | 4,846.60 mi (7,799.84 km) |
| Gretna to Oud-Beijerland | 4,801.34 mi (7,727.01 km) |
| Gretna to Oudenbosch | 4,812.31 mi (7,744.67 km) |
