There are
405 mi
from Duluth, MN to Marshalltown, IA
That's the driving distance. It would take 7 hours 28 mins to go from Duluth, Minnesota to Marshalltown, Iowa.
The flight distance (direct flight from Duluth, MN to Marshalltown, IA) is 329.72 mi.
405 mi = 651.04 kms