| Niagara Falls to Popovo | 4,889.95 mi (7,869.62 km) |
| Niagara Falls to Provadia | 4,942.49 mi (7,954.16 km) |
| Niagara Falls to Radnevo | 4,926.97 mi (7,929.20 km) |
| Niagara Falls to Radomir | 4,800.92 mi (7,726.34 km) |
| Niagara Falls to Rakitovo | 4,870.39 mi (7,838.14 km) |
| Niagara Falls to Rakovski | 4,890.53 mi (7,870.54 km) |
| Niagara Falls to Razgrad | 4,892.11 mi (7,873.10 km) |
| Niagara Falls to Razlog | 4,850.95 mi (7,806.85 km) |
| Niagara Falls to Ruse | 4,857.79 mi (7,817.86 km) |
| Niagara Falls to Samokov | 4,833.95 mi (7,779.50 km) |
| Niagara Falls to Sandanski | 4,857.95 mi (7,818.12 km) |
| Niagara Falls to Sevlievo | 4,862.54 mi (7,825.51 km) |
| Niagara Falls to Shumen | 4,919.21 mi (7,916.71 km) |
| Niagara Falls to Silistra | 4,892.72 mi (7,874.06 km) |
| Niagara Falls to Sliven | 4,924.45 mi (7,925.14 km) |
