| Southborough to Devnya | 1,384.17 mi (2,227.61 km) |
| Southborough to Dimitrovgrad | 1,347.84 mi (2,169.14 km) |
| Southborough to Dobrich | 1,382.50 mi (2,224.92 km) |
| Southborough to Dospat | 1,306.05 mi (2,101.88 km) |
| Southborough to Dupnitsa | 1,237.45 mi (1,991.48 km) |
| Southborough to Elhovo | 1,383.12 mi (2,225.91 km) |
| Southborough to Etropole | 1,250.04 mi (2,011.74 km) |
| Southborough to Gabrovo | 1,303.91 mi (2,098.44 km) |
| Southborough to Gorna Oryahovitsa | 1,308.82 mi (2,106.34 km) |
| Southborough to Gotse Delchev | 1,292.14 mi (2,079.49 km) |
| Southborough to Harmanli | 1,365.02 mi (2,196.79 km) |
| Southborough to Haskovo | 1,351.29 mi (2,174.69 km) |
| Southborough to Ihtiman | 1,258.65 mi (2,025.60 km) |
| Southborough to Isperih | 1,334.60 mi (2,147.84 km) |
| Southborough to Kardzhali | 1,354.91 mi (2,180.51 km) |
