| Boise to Popovo | 5,997.30 mi (9,651.72 km) |
| Boise to Provadia | 6,033.97 mi (9,710.74 km) |
| Boise to Radnevo | 6,055.59 mi (9,745.54 km) |
| Boise to Radomir | 5,970.34 mi (9,608.33 km) |
| Boise to Rakitovo | 6,032.08 mi (9,707.70 km) |
| Boise to Rakovski | 6,034.08 mi (9,710.91 km) |
| Boise to Razgrad | 5,992.19 mi (9,643.50 km) |
| Boise to Razlog | 6,023.43 mi (9,693.77 km) |
| Boise to Ruse | 5,961.80 mi (9,594.59 km) |
| Boise to Samokov | 5,997.86 mi (9,652.62 km) |
| Boise to Sandanski | 6,038.18 mi (9,717.52 km) |
| Boise to Sevlievo | 5,992.09 mi (9,643.34 km) |
| Boise to Shumen | 6,016.87 mi (9,683.21 km) |
| Boise to Silistra | 5,972.02 mi (9,611.03 km) |
| Boise to Sliven | 6,040.87 mi (9,721.83 km) |
