| Fort Collins to Smolyan | 5,949.37 mi (9,574.58 km) |
| Fort Collins to Sofia | 5,845.64 mi (9,407.65 km) |
| Fort Collins to Sopot | 5,891.12 mi (9,480.85 km) |
| Fort Collins to Sozopol | 5,990.30 mi (9,640.45 km) |
| Fort Collins to Sredets | 5,979.79 mi (9,623.55 km) |
| Fort Collins to Stamboliyski | 5,913.56 mi (9,516.95 km) |
| Fort Collins to Stara Zagora | 5,929.95 mi (9,543.33 km) |
| Fort Collins to Svilengrad | 5,983.84 mi (9,630.07 km) |
| Fort Collins to Svishtov | 5,854.52 mi (9,421.94 km) |
| Fort Collins to Targovishte | 5,910.84 mi (9,512.58 km) |
| Fort Collins to Teteven | 5,861.81 mi (9,433.67 km) |
| Fort Collins to Troyan | 5,877.07 mi (9,458.23 km) |
| Fort Collins to Tryavna | 5,901.10 mi (9,496.90 km) |
| Fort Collins to Tutrakan | 5,866.36 mi (9,441.00 km) |
| Fort Collins to Varna | 5,950.55 mi (9,576.49 km) |
