| Portland to Smolyan | 6,089.51 mi (9,800.11 km) |
| Portland to Sofia | 5,991.27 mi (9,642.01 km) |
| Portland to Sopot | 6,022.24 mi (9,691.86 km) |
| Portland to Sozopol | 6,091.68 mi (9,803.62 km) |
| Portland to Sredets | 6,087.09 mi (9,796.22 km) |
| Portland to Stamboliyski | 6,051.09 mi (9,738.29 km) |
| Portland to Stara Zagora | 6,053.23 mi (9,741.73 km) |
| Portland to Svilengrad | 6,106.40 mi (9,827.30 km) |
| Portland to Svishtov | 5,971.66 mi (9,610.46 km) |
| Portland to Targovishte | 6,017.85 mi (9,684.79 km) |
| Portland to Teteven | 5,995.87 mi (9,649.43 km) |
| Portland to Troyan | 6,006.68 mi (9,666.81 km) |
| Portland to Tryavna | 6,022.57 mi (9,692.39 km) |
| Portland to Tutrakan | 5,966.85 mi (9,602.72 km) |
| Portland to Varna | 6,043.61 mi (9,726.25 km) |
