There are
938 mi
from Killeen, TX to Marshalltown, IA
That's the driving distance. It would take 16 hours 32 mins to go from Killeen, Texas to Marshalltown, Iowa.
The flight distance (direct flight from Killeen, TX to Marshalltown, IA) is 800.92 mi.
938 mi = 1,510.29 kms