| Prospect Heights to Popovo | 5,261.23 mi (8,467.13 km) |
| Prospect Heights to Provadia | 5,311.36 mi (8,547.81 km) |
| Prospect Heights to Radnevo | 5,302.64 mi (8,533.78 km) |
| Prospect Heights to Radomir | 5,182.80 mi (8,340.91 km) |
| Prospect Heights to Rakitovo | 5,251.57 mi (8,451.59 km) |
| Prospect Heights to Rakovski | 5,268.57 mi (8,478.95 km) |
| Prospect Heights to Razgrad | 5,262.04 mi (8,468.44 km) |
| Prospect Heights to Razlog | 5,233.90 mi (8,423.15 km) |
| Prospect Heights to Ruse | 5,228.07 mi (8,413.77 km) |
| Prospect Heights to Samokov | 5,215.16 mi (8,392.98 km) |
| Prospect Heights to Sandanski | 5,242.39 mi (8,436.82 km) |
| Prospect Heights to Sevlievo | 5,237.68 mi (8,429.23 km) |
| Prospect Heights to Shumen | 5,288.99 mi (8,511.81 km) |
| Prospect Heights to Silistra | 5,258.70 mi (8,463.06 km) |
| Prospect Heights to Sliven | 5,297.81 mi (8,526.01 km) |
