There are
485 mi
from Gaithersburg, MD to Sevierville, TN
That's the driving distance. It would take 8 hours 58 mins to go from Gaithersburg, Maryland to Sevierville, Tennessee.
The flight distance (direct flight from Gaithersburg, MD to Sevierville, TN) is 415.46 mi.
485 mi = 780.19 kms