There are
740 mi
from Amarillo, TX to Chesterfield, MO
That's the driving distance. It would take 13 hours 6 mins to go from Amarillo, Texas to Chesterfield, Missouri.
The flight distance (direct flight from Amarillo, TX to Chesterfield, MO) is 664.82 mi.
740 mi = 1,190.28 kms