There are
762 mi
from Amarillo, TX to Florissant, MO
That's the driving distance. It would take 13 hours 27 mins to go from Amarillo, Texas to Florissant, Missouri.
The flight distance (direct flight from Amarillo, TX to Florissant, MO) is 680.53 mi.
762 mi = 1,227.01 kms