| Grefrath to Popovo | 1,077.39 mi (1,733.89 km) |
| Grefrath to Provadia | 1,132.32 mi (1,822.30 km) |
| Grefrath to Radnevo | 1,111.60 mi (1,788.95 km) |
| Grefrath to Radomir | 987.29 mi (1,588.89 km) |
| Grefrath to Rakitovo | 1,056.23 mi (1,699.84 km) |
| Grefrath to Rakovski | 1,075.04 mi (1,730.10 km) |
| Grefrath to Razgrad | 1,081.00 mi (1,739.71 km) |
| Grefrath to Razlog | 1,038.37 mi (1,671.10 km) |
| Grefrath to Ruse | 1,046.49 mi (1,684.16 km) |
| Grefrath to Samokov | 1,019.80 mi (1,641.20 km) |
| Grefrath to Sandanski | 1,047.18 mi (1,685.27 km) |
| Grefrath to Sevlievo | 1,047.40 mi (1,685.63 km) |
| Grefrath to Shumen | 1,108.10 mi (1,783.32 km) |
| Grefrath to Silistra | 1,087.46 mi (1,750.10 km) |
| Grefrath to Sliven | 1,110.08 mi (1,786.51 km) |
