| South Portland to Devnya | 4,587.61 mi (7,383.05 km) |
| South Portland to Dimitrovgrad | 4,558.99 mi (7,336.99 km) |
| South Portland to Dobrich | 4,583.02 mi (7,375.66 km) |
| South Portland to Dospat | 4,517.55 mi (7,270.29 km) |
| South Portland to Dupnitsa | 4,448.96 mi (7,159.91 km) |
| South Portland to Elhovo | 4,592.96 mi (7,391.65 km) |
| South Portland to Etropole | 4,461.32 mi (7,179.80 km) |
| South Portland to Gabrovo | 4,513.68 mi (7,264.07 km) |
| South Portland to Gorna Oryahovitsa | 4,517.12 mi (7,269.61 km) |
| South Portland to Gotse Delchev | 4,503.25 mi (7,247.28 km) |
| South Portland to Harmanli | 4,576.09 mi (7,364.51 km) |
| South Portland to Haskovo | 4,562.61 mi (7,342.81 km) |
| South Portland to Ihtiman | 4,470.32 mi (7,194.28 km) |
| South Portland to Isperih | 4,537.34 mi (7,302.15 km) |
| South Portland to Kardzhali | 4,566.54 mi (7,349.14 km) |
