| Hillsboro to Smolyan | 6,095.69 mi (9,810.07 km) |
| Hillsboro to Sofia | 5,997.56 mi (9,652.14 km) |
| Hillsboro to Sopot | 6,028.33 mi (9,701.66 km) |
| Hillsboro to Sozopol | 6,097.35 mi (9,812.73 km) |
| Hillsboro to Sredets | 6,092.83 mi (9,805.47 km) |
| Hillsboro to Stamboliyski | 6,057.26 mi (9,748.21 km) |
| Hillsboro to Stara Zagora | 6,059.20 mi (9,751.34 km) |
| Hillsboro to Svilengrad | 6,112.35 mi (9,836.87 km) |
| Hillsboro to Svishtov | 5,977.58 mi (9,619.99 km) |
| Hillsboro to Targovishte | 6,023.62 mi (9,694.08 km) |
| Hillsboro to Teteven | 6,002.02 mi (9,659.31 km) |
| Hillsboro to Troyan | 6,012.76 mi (9,676.60 km) |
| Hillsboro to Tryavna | 6,028.53 mi (9,701.99 km) |
| Hillsboro to Tutrakan | 5,972.56 mi (9,611.90 km) |
| Hillsboro to Varna | 6,049.18 mi (9,735.22 km) |
