There are
2,632 mi
from San Diego, CA to Gaithersburg, MD
That's the driving distance. It would take 1 day 23 hours to go from San Diego, California to Gaithersburg, Maryland.
The flight distance (direct flight from San Diego, CA to Gaithersburg, MD) is 2,260.36 mi.
2,632 mi = 3.22 kms