| Frederick to Popovo | 4,997.63 mi (8,042.91 km) |
| Frederick to Provadia | 5,052.11 mi (8,130.58 km) |
| Frederick to Radnevo | 5,030.40 mi (8,095.65 km) |
| Frederick to Radomir | 4,898.91 mi (7,884.04 km) |
| Frederick to Rakitovo | 4,968.76 mi (7,996.45 km) |
| Frederick to Rakovski | 4,991.85 mi (8,033.61 km) |
| Frederick to Razgrad | 5,001.01 mi (8,048.34 km) |
| Frederick to Razlog | 4,947.65 mi (7,962.47 km) |
| Frederick to Ruse | 4,966.52 mi (7,992.84 km) |
| Frederick to Samokov | 4,932.46 mi (7,938.02 km) |
| Frederick to Sandanski | 4,953.13 mi (7,971.29 km) |
| Frederick to Sevlievo | 4,966.75 mi (7,993.22 km) |
| Frederick to Shumen | 5,028.12 mi (8,091.98 km) |
| Frederick to Silistra | 5,005.13 mi (8,054.99 km) |
| Frederick to Sliven | 5,030.05 mi (8,095.08 km) |
