| South Portland to Noventa Vicentina | 3,852.20 mi (6,199.51 km) |
| South Portland to Novi di Modena | 3,838.88 mi (6,178.08 km) |
| South Portland to Novi Ligure | 3,753.13 mi (6,040.08 km) |
| South Portland to Nuoro | 3,932.58 mi (6,328.87 km) |
| South Portland to Occhiobello | 3,866.73 mi (6,222.90 km) |
| South Portland to Oderzo | 3,875.23 mi (6,236.57 km) |
| South Portland to Oggiono | 3,743.13 mi (6,023.98 km) |
| South Portland to Olbia | 3,918.24 mi (6,305.80 km) |
| South Portland to Oleggio | 3,718.76 mi (5,984.76 km) |
| South Portland to Olgiate Comasco | 3,726.89 mi (5,997.85 km) |
| South Portland to Olgiate Olona | 3,728.29 mi (6,000.10 km) |
| South Portland to Omegna | 3,700.05 mi (5,954.66 km) |
| South Portland to Opera | 3,750.73 mi (6,036.22 km) |
| South Portland to Oppeano | 3,836.87 mi (6,174.84 km) |
| South Portland to Orbassano | 3,691.25 mi (5,940.50 km) |
