There are
1,521 mi
from Boynton Beach, FL to Johnston, IA
That's the driving distance. It would take 1 day 4 hours to go from Boynton Beach, Florida to Johnston, Iowa.
The flight distance (direct flight from Boynton Beach, FL to Johnston, IA) is 1,301.83 mi.
1,521 mi = 1.61 kms