| Hackettstown to Smolyan | 4,842.83 mi (7,793.78 km) |
| Hackettstown to Sofia | 4,740.34 mi (7,628.85 km) |
| Hackettstown to Sopot | 4,800.14 mi (7,725.08 km) |
| Hackettstown to Sozopol | 4,928.41 mi (7,931.52 km) |
| Hackettstown to Sredets | 4,911.37 mi (7,904.09 km) |
| Hackettstown to Stamboliyski | 4,812.94 mi (7,745.68 km) |
| Hackettstown to Stara Zagora | 4,845.61 mi (7,798.26 km) |
| Hackettstown to Svilengrad | 4,896.18 mi (7,879.64 km) |
| Hackettstown to Svishtov | 4,783.83 mi (7,698.83 km) |
| Hackettstown to Targovishte | 4,848.31 mi (7,802.60 km) |
| Hackettstown to Teteven | 4,769.48 mi (7,675.74 km) |
| Hackettstown to Troyan | 4,789.06 mi (7,707.24 km) |
| Hackettstown to Tryavna | 4,821.28 mi (7,759.11 km) |
| Hackettstown to Tutrakan | 4,815.69 mi (7,750.11 km) |
| Hackettstown to Varna | 4,902.39 mi (7,889.63 km) |
