There are
1,557 mi
from Sioux Falls, SD to Watertown, MA
That's the driving distance. It would take 1 day 4 hours to go from Sioux Falls, South Dakota to Watertown, Massachusetts.
The flight distance (direct flight from Sioux Falls, SD to Watertown, MA) is 1,287.77 mi.
1,557 mi = 1.61 kms