| Rock Island to Popovo | 5,385.76 mi (8,667.55 km) |
| Rock Island to Provadia | 5,435.22 mi (8,747.15 km) |
| Rock Island to Radnevo | 5,428.29 mi (8,735.99 km) |
| Rock Island to Radomir | 5,310.15 mi (8,545.86 km) |
| Rock Island to Rakitovo | 5,378.69 mi (8,656.17 km) |
| Rock Island to Rakovski | 5,394.87 mi (8,682.20 km) |
| Rock Island to Razgrad | 5,386.22 mi (8,668.28 km) |
| Rock Island to Razlog | 5,361.50 mi (8,628.49 km) |
| Rock Island to Ruse | 5,352.37 mi (8,613.81 km) |
| Rock Island to Samokov | 5,342.31 mi (8,597.62 km) |
| Rock Island to Sandanski | 5,370.36 mi (8,642.77 km) |
| Rock Island to Sevlievo | 5,363.24 mi (8,631.31 km) |
| Rock Island to Shumen | 5,413.11 mi (8,711.55 km) |
| Rock Island to Silistra | 5,381.84 mi (8,661.24 km) |
| Rock Island to Sliven | 5,422.87 mi (8,727.26 km) |
