There are
1,421 mi
from Flagstaff, AZ to Watertown, SD
That's the driving distance. It would take 1 day 1 hour to go from Flagstaff, Arizona to Watertown, South Dakota.
The flight distance (direct flight from Flagstaff, AZ to Watertown, SD) is 1,016.54 mi.
1,421 mi = 2,287.13 kms