| Northglenn to Smolyan | 5,982.67 mi (9,628.18 km) |
| Northglenn to Sofia | 5,878.86 mi (9,461.12 km) |
| Northglenn to Sopot | 5,924.76 mi (9,534.98 km) |
| Northglenn to Sozopol | 6,024.75 mi (9,695.89 km) |
| Northglenn to Sredets | 6,014.08 mi (9,678.72 km) |
| Northglenn to Stamboliyski | 5,946.97 mi (9,570.73 km) |
| Northglenn to Stara Zagora | 5,963.79 mi (9,597.79 km) |
| Northglenn to Svilengrad | 6,017.66 mi (9,684.49 km) |
| Northglenn to Svishtov | 5,888.61 mi (9,476.81 km) |
| Northglenn to Targovishte | 5,945.19 mi (9,567.86 km) |
| Northglenn to Teteven | 5,895.38 mi (9,487.70 km) |
| Northglenn to Troyan | 5,910.77 mi (9,512.46 km) |
| Northglenn to Tryavna | 5,935.02 mi (9,551.49 km) |
| Northglenn to Tutrakan | 5,900.94 mi (9,496.65 km) |
| Northglenn to Varna | 5,985.28 mi (9,632.38 km) |
