There are
1,545 mi
from Amarillo, TX to Gaithersburg, MD
That's the driving distance. It would take 1 day 4 hours to go from Amarillo, Texas to Gaithersburg, Maryland.
The flight distance (direct flight from Amarillo, TX to Gaithersburg, MD) is 1,378.12 mi.
1,545 mi = 1.61 kms