There are
1,784 mi
from Walnut Creek, CA to Johnston, IA
That's the driving distance. It would take 1 day 6 hours to go from Walnut Creek, California to Johnston, Iowa.
The flight distance (direct flight from Walnut Creek, CA to Johnston, IA) is 1,520.84 mi.
1,784 mi = 2,870.63 kms