There are
2,503 mi
from Gaithersburg, MD to Barstow, CA
That's the driving distance. It would take 1 day 20 hours to go from Gaithersburg, Maryland to Barstow, California.
The flight distance (direct flight from Gaithersburg, MD to Barstow, CA) is 2,198.29 mi.
2,503 mi = 4,028.27 kms