| Duluth to Popovo | 5,162.61 mi (8,308.42 km) |
| Duluth to Provadia | 5,209.09 mi (8,383.21 km) |
| Duluth to Radnevo | 5,209.77 mi (8,384.32 km) |
| Duluth to Radomir | 5,099.79 mi (8,207.31 km) |
| Duluth to Rakitovo | 5,166.99 mi (8,315.46 km) |
| Duluth to Rakovski | 5,179.34 mi (8,335.35 km) |
| Duluth to Razgrad | 5,161.58 mi (8,306.76 km) |
| Duluth to Razlog | 5,152.06 mi (8,291.44 km) |
| Duluth to Ruse | 5,128.37 mi (8,253.31 km) |
| Duluth to Samokov | 5,130.91 mi (8,257.40 km) |
| Duluth to Sandanski | 5,162.68 mi (8,308.54 km) |
| Duluth to Sevlievo | 5,144.60 mi (8,279.43 km) |
| Duluth to Shumen | 5,188.11 mi (8,349.45 km) |
| Duluth to Silistra | 5,152.99 mi (8,292.93 km) |
| Duluth to Sliven | 5,201.77 mi (8,371.44 km) |
