| Piqua to Nuth | 4,148.15 mi (6,675.81 km) |
| Piqua to Oegstgeest | 4,053.92 mi (6,524.15 km) |
| Piqua to Oirschot | 4,107.04 mi (6,609.64 km) |
| Piqua to Oisterwijk | 4,100.58 mi (6,599.24 km) |
| Piqua to Oldebroek | 4,099.55 mi (6,597.59 km) |
| Piqua to Oldenzaal | 4,142.43 mi (6,666.59 km) |
| Piqua to Ommen | 4,116.72 mi (6,625.23 km) |
| Piqua to Oosterend | 4,088.26 mi (6,579.41 km) |
| Piqua to Oosterhout | 4,085.60 mi (6,575.13 km) |
| Piqua to Oosterwolde | 4,097.00 mi (6,593.48 km) |
| Piqua to Oostzaan | 4,061.92 mi (6,537.02 km) |
| Piqua to Opmeer | 4,056.17 mi (6,527.77 km) |
| Piqua to Oss | 4,106.80 mi (6,609.26 km) |
| Piqua to Oud-Beijerland | 4,062.73 mi (6,538.34 km) |
| Piqua to Oudenbosch | 4,074.56 mi (6,557.37 km) |
