There are
2,865 mi
from Gaithersburg, MD to Watsonville, CA
That's the driving distance. It would take 2 days 2 hours to go from Gaithersburg, Maryland to Watsonville, California.
The flight distance (direct flight from Gaithersburg, MD to Watsonville, CA) is 2,405.50 mi.
2,865 mi = 4,610.29 kms