There are
394 mi
from Rockford, IL to South Sioux City, NE
That's the driving distance. It would take 8 hours 10 mins to go from Rockford, Illinois to South Sioux City, Nebraska.
The flight distance (direct flight from Rockford, IL to South Sioux City, NE) is 373.70 mi.
394 mi = 633.73 kms