| Gaithersburg to Popovo | 5,003.51 mi (8,052.38 km) |
| Gaithersburg to Provadia | 5,058.16 mi (8,140.33 km) |
| Gaithersburg to Radnevo | 5,035.89 mi (8,104.48 km) |
| Gaithersburg to Radomir | 4,903.93 mi (7,892.11 km) |
| Gaithersburg to Rakitovo | 4,973.80 mi (8,004.56 km) |
| Gaithersburg to Rakovski | 4,997.15 mi (8,042.14 km) |
| Gaithersburg to Razgrad | 5,007.01 mi (8,058.00 km) |
| Gaithersburg to Razlog | 4,952.53 mi (7,970.33 km) |
| Gaithersburg to Ruse | 4,972.51 mi (8,002.48 km) |
| Gaithersburg to Samokov | 4,937.51 mi (7,946.16 km) |
| Gaithersburg to Sandanski | 4,957.88 mi (7,978.93 km) |
| Gaithersburg to Sevlievo | 4,972.33 mi (8,002.19 km) |
| Gaithersburg to Shumen | 5,034.12 mi (8,101.63 km) |
| Gaithersburg to Silistra | 5,011.46 mi (8,065.16 km) |
| Gaithersburg to Sliven | 5,035.74 mi (8,104.23 km) |
