There are
981 mi
from Marshalltown, IA to Sulphur, LA
That's the driving distance. It would take 18 hours 44 mins to go from Marshalltown, Iowa to Sulphur, Louisiana.
The flight distance (direct flight from Marshalltown, IA to Sulphur, LA) is 816.61 mi.
981 mi = 1,578.12 kms