| Dumbarton to Noventa Vicentina | 1,015.65 mi (1,634.53 km) |
| Dumbarton to Novi di Modena | 1,018.73 mi (1,639.48 km) |
| Dumbarton to Novi Ligure | 968.23 mi (1,558.22 km) |
| Dumbarton to Nuoro | 1,250.74 mi (2,012.86 km) |
| Dumbarton to Occhiobello | 1,036.93 mi (1,668.78 km) |
| Dumbarton to Oderzo | 1,018.14 mi (1,638.54 km) |
| Dumbarton to Oggiono | 924.81 mi (1,488.34 km) |
| Dumbarton to Olbia | 1,217.39 mi (1,959.20 km) |
| Dumbarton to Oleggio | 915.51 mi (1,473.37 km) |
| Dumbarton to Olgiate Comasco | 914.15 mi (1,471.19 km) |
| Dumbarton to Olgiate Olona | 920.39 mi (1,481.22 km) |
| Dumbarton to Omegna | 893.47 mi (1,437.91 km) |
| Dumbarton to Opera | 943.76 mi (1,518.84 km) |
| Dumbarton to Oppeano | 1,004.38 mi (1,616.39 km) |
| Dumbarton to Orbassano | 921.72 mi (1,483.36 km) |
