| Glen Carbon to Popovo | 5,504.94 mi (8,859.34 km) |
| Glen Carbon to Provadia | 5,555.75 mi (8,941.11 km) |
| Glen Carbon to Radnevo | 5,545.11 mi (8,923.99 km) |
| Glen Carbon to Radomir | 5,423.26 mi (8,727.89 km) |
| Glen Carbon to Rakitovo | 5,492.30 mi (8,839.00 km) |
| Glen Carbon to Rakovski | 5,510.30 mi (8,867.97 km) |
| Glen Carbon to Razgrad | 5,506.12 mi (8,861.24 km) |
| Glen Carbon to Razlog | 5,474.03 mi (8,809.60 km) |
| Glen Carbon to Ruse | 5,472.04 mi (8,806.40 km) |
| Glen Carbon to Samokov | 5,455.86 mi (8,780.35 km) |
| Glen Carbon to Sandanski | 5,482.02 mi (8,822.46 km) |
| Glen Carbon to Sevlievo | 5,480.27 mi (8,819.65 km) |
| Glen Carbon to Shumen | 5,533.12 mi (8,904.70 km) |
| Glen Carbon to Silistra | 5,503.81 mi (8,857.52 km) |
| Glen Carbon to Sliven | 5,540.95 mi (8,917.30 km) |
