There are
843 mi
from Gaithersburg, MD to Tupelo, MS
That's the driving distance. It would take 15 hours 58 mins to go from Gaithersburg, Maryland to Tupelo, Mississippi.
The flight distance (direct flight from Gaithersburg, MD to Tupelo, MS) is 720.28 mi.
843 mi = 1,356.87 kms