| Fort Collins to Popovo | 5,895.12 mi (9,487.27 km) |
| Fort Collins to Provadia | 5,938.85 mi (9,557.65 km) |
| Fort Collins to Radnevo | 5,945.81 mi (9,568.86 km) |
| Fort Collins to Radomir | 5,842.35 mi (9,402.35 km) |
| Fort Collins to Rakitovo | 5,908.33 mi (9,508.54 km) |
| Fort Collins to Rakovski | 5,917.81 mi (9,523.80 km) |
| Fort Collins to Razgrad | 5,892.85 mi (9,483.63 km) |
| Fort Collins to Razlog | 5,895.07 mi (9,487.20 km) |
| Fort Collins to Ruse | 5,860.33 mi (9,431.28 km) |
| Fort Collins to Samokov | 5,872.61 mi (9,451.05 km) |
| Fort Collins to Sandanski | 5,906.86 mi (9,506.18 km) |
| Fort Collins to Sevlievo | 5,880.81 mi (9,464.25 km) |
| Fort Collins to Shumen | 5,918.95 mi (9,525.62 km) |
| Fort Collins to Silistra | 5,880.65 mi (9,463.99 km) |
| Fort Collins to Sliven | 5,935.79 mi (9,552.73 km) |
