| South Portland to Nasaud | 4,295.92 mi (6,913.61 km) |
| South Portland to Navodari | 4,580.84 mi (7,372.16 km) |
| South Portland to Negresti-Oas | 4,235.18 mi (6,815.87 km) |
| South Portland to Nehoiu | 4,447.81 mi (7,158.05 km) |
| South Portland to Ocna Mures | 4,310.60 mi (6,937.25 km) |
| South Portland to Odobesti | 4,459.86 mi (7,177.45 km) |
| South Portland to Odorheiu Secuiesc | 4,369.42 mi (7,031.91 km) |
| South Portland to Oltenita | 4,513.92 mi (7,264.46 km) |
| South Portland to Onesti | 4,427.95 mi (7,126.09 km) |
| South Portland to Oradea | 4,208.30 mi (6,772.61 km) |
| South Portland to Orastie | 4,306.44 mi (6,930.55 km) |
| South Portland to Oravita | 4,278.59 mi (6,885.72 km) |
| South Portland to Orsova | 4,319.57 mi (6,951.67 km) |
| South Portland to Otelu Rosu | 4,286.22 mi (6,898.01 km) |
| South Portland to Otopeni | 4,472.21 mi (7,197.32 km) |
