There are
1,438 mi
from Rapid City, SD to Johnstown, PA
That's the driving distance. It would take 1 day 1 hour to go from Rapid City, South Dakota to Johnstown, Pennsylvania.
The flight distance (direct flight from Rapid City, SD to Johnstown, PA) is 1,266.01 mi.
1,438 mi = 2,314.71 kms