There are
2,785 mi
from Gaithersburg, MD to San Ramon, CA
That's the driving distance. It would take 2 days to go from Gaithersburg, Maryland to San Ramon, California.
The flight distance (direct flight from Gaithersburg, MD to San Ramon, CA) is 2,399.48 mi.
2,785 mi = 4,482.53 kms