There are
1,685 mi
from Rancho Cucamonga, CA to Watertown, SD
That's the driving distance. It would take 1 day 5 hours to go from Rancho Cucamonga, California to Watertown, South Dakota.
The flight distance (direct flight from Rancho Cucamonga, CA to Watertown, SD) is 1,316.07 mi.
1,685 mi = 1.61 kms