| South Sioux City to Popovo | 5,525.86 mi (8,893.01 km) |
| South Sioux City to Provadia | 5,572.63 mi (8,968.28 km) |
| South Sioux City to Radnevo | 5,572.53 mi (8,968.12 km) |
| South Sioux City to Radomir | 5,461.42 mi (8,789.31 km) |
| South Sioux City to Rakitovo | 5,528.85 mi (8,897.82 km) |
| South Sioux City to Rakovski | 5,541.72 mi (8,918.54 km) |
| South Sioux City to Razgrad | 5,524.98 mi (8,891.59 km) |
| South Sioux City to Razlog | 5,513.58 mi (8,873.26 km) |
| South Sioux City to Ruse | 5,491.69 mi (8,838.03 km) |
| South Sioux City to Samokov | 5,492.71 mi (8,839.66 km) |
| South Sioux City to Sandanski | 5,523.94 mi (8,889.93 km) |
| South Sioux City to Sevlievo | 5,507.35 mi (8,863.22 km) |
| South Sioux City to Shumen | 5,551.54 mi (8,934.35 km) |
| South Sioux City to Silistra | 5,516.75 mi (8,878.35 km) |
| South Sioux City to Sliven | 5,564.82 mi (8,955.71 km) |
