There are
1,560 mi
from Rapid City, SD to Slidell, LA
That's the driving distance. It would take 1 day 3 hours to go from Rapid City, South Dakota to Slidell, Louisiana.
The flight distance (direct flight from Rapid City, SD to Slidell, LA) is 1,204.11 mi.
1,560 mi = 2,509.88 kms