| Potomac to Noventa Vicentina | 4,328.51 mi (6,966.06 km) |
| Potomac to Novi di Modena | 4,314.54 mi (6,943.58 km) |
| Potomac to Novi Ligure | 4,227.68 mi (6,803.80 km) |
| Potomac to Nuoro | 4,400.74 mi (7,082.31 km) |
| Potomac to Occhiobello | 4,342.70 mi (6,988.90 km) |
| Potomac to Oderzo | 4,352.32 mi (7,004.38 km) |
| Potomac to Oggiono | 4,219.09 mi (6,789.97 km) |
| Potomac to Olbia | 4,387.58 mi (7,061.13 km) |
| Potomac to Oleggio | 4,194.24 mi (6,749.97 km) |
| Potomac to Olgiate Comasco | 4,202.71 mi (6,763.61 km) |
| Potomac to Olgiate Olona | 4,203.91 mi (6,765.54 km) |
| Potomac to Omegna | 4,175.75 mi (6,720.22 km) |
| Potomac to Opera | 4,226.21 mi (6,801.43 km) |
| Potomac to Oppeano | 4,313.06 mi (6,941.19 km) |
| Potomac to Orbassano | 4,165.53 mi (6,703.77 km) |
