| Houghton Regis to Popovo | 1,368.61 mi (2,202.56 km) |
| Houghton Regis to Provadia | 1,424.73 mi (2,292.88 km) |
| Houghton Regis to Radnevo | 1,399.17 mi (2,251.75 km) |
| Houghton Regis to Radomir | 1,268.69 mi (2,041.76 km) |
| Houghton Regis to Rakitovo | 1,338.37 mi (2,153.89 km) |
| Houghton Regis to Rakovski | 1,360.53 mi (2,189.56 km) |
| Houghton Regis to Razgrad | 1,373.10 mi (2,209.79 km) |
| Houghton Regis to Razlog | 1,318.33 mi (2,121.65 km) |
| Houghton Regis to Ruse | 1,338.58 mi (2,154.24 km) |
| Houghton Regis to Samokov | 1,301.97 mi (2,095.32 km) |
| Houghton Regis to Sandanski | 1,325.16 mi (2,132.64 km) |
| Houghton Regis to Sevlievo | 1,335.77 mi (2,149.72 km) |
| Houghton Regis to Shumen | 1,400.12 mi (2,253.27 km) |
| Houghton Regis to Silistra | 1,381.68 mi (2,223.61 km) |
| Houghton Regis to Sliven | 1,399.57 mi (2,252.39 km) |
