There are
2,782 mi
from Gaithersburg, MD to Danville, CA
That's the driving distance. It would take 2 days to go from Gaithersburg, Maryland to Danville, California.
The flight distance (direct flight from Gaithersburg, MD to Danville, CA) is 2,399.82 mi.
2,782 mi = 4,476.46 kms