| Port Huron to Popovo | 5,021.78 mi (8,081.77 km) |
| Port Huron to Provadia | 5,073.33 mi (8,164.74 km) |
| Port Huron to Radnevo | 5,060.68 mi (8,144.37 km) |
| Port Huron to Radomir | 4,937.19 mi (7,945.64 km) |
| Port Huron to Rakitovo | 5,006.40 mi (8,057.02 km) |
| Port Huron to Rakovski | 5,025.21 mi (8,087.30 km) |
| Port Huron to Razgrad | 5,023.37 mi (8,084.33 km) |
| Port Huron to Razlog | 4,987.70 mi (8,026.93 km) |
| Port Huron to Ruse | 4,989.18 mi (8,029.30 km) |
| Port Huron to Samokov | 4,969.95 mi (7,998.36 km) |
| Port Huron to Sandanski | 4,995.34 mi (8,039.23 km) |
| Port Huron to Sevlievo | 4,995.98 mi (8,040.26 km) |
| Port Huron to Shumen | 5,050.42 mi (8,127.87 km) |
| Port Huron to Silistra | 5,022.31 mi (8,082.63 km) |
| Port Huron to Sliven | 5,057.18 mi (8,138.74 km) |
