| Mercer Island to Popovo | 5,867.80 mi (9,443.32 km) |
| Mercer Island to Provadia | 5,899.62 mi (9,494.51 km) |
| Mercer Island to Radnevo | 5,930.20 mi (9,543.74 km) |
| Mercer Island to Radomir | 5,857.58 mi (9,426.87 km) |
| Mercer Island to Rakitovo | 5,915.87 mi (9,520.67 km) |
| Mercer Island to Rakovski | 5,913.06 mi (9,516.15 km) |
| Mercer Island to Razgrad | 5,860.97 mi (9,432.32 km) |
| Mercer Island to Razlog | 5,910.27 mi (9,511.66 km) |
| Mercer Island to Ruse | 5,832.28 mi (9,386.15 km) |
| Mercer Island to Samokov | 5,883.01 mi (9,467.80 km) |
| Mercer Island to Sandanski | 5,926.76 mi (9,538.20 km) |
| Mercer Island to Sevlievo | 5,868.41 mi (9,444.29 km) |
| Mercer Island to Shumen | 5,884.46 mi (9,470.12 km) |
| Mercer Island to Silistra | 5,836.04 mi (9,392.20 km) |
| Mercer Island to Sliven | 5,912.68 mi (9,515.53 km) |
