| Northolt to Popovo | 1,355.99 mi (2,182.26 km) |
| Northolt to Provadia | 1,412.52 mi (2,273.23 km) |
| Northolt to Radnevo | 1,385.46 mi (2,229.68 km) |
| Northolt to Radomir | 1,253.69 mi (2,017.62 km) |
| Northolt to Rakitovo | 1,323.45 mi (2,129.89 km) |
| Northolt to Rakovski | 1,346.33 mi (2,166.71 km) |
| Northolt to Razgrad | 1,360.79 mi (2,189.98 km) |
| Northolt to Razlog | 1,303.01 mi (2,097.00 km) |
| Northolt to Ruse | 1,326.29 mi (2,134.46 km) |
| Northolt to Samokov | 1,287.09 mi (2,071.38 km) |
| Northolt to Sandanski | 1,309.49 mi (2,107.41 km) |
| Northolt to Sevlievo | 1,322.31 mi (2,128.05 km) |
| Northolt to Shumen | 1,387.77 mi (2,233.39 km) |
| Northolt to Silistra | 1,370.29 mi (2,205.26 km) |
| Northolt to Sliven | 1,386.39 mi (2,231.17 km) |
