There are
2,760 mi
from Gaithersburg, MD to Manteca, CA
That's the driving distance. It would take 2 days to go from Gaithersburg, Maryland to Manteca, California.
The flight distance (direct flight from Gaithersburg, MD to Manteca, CA) is 2,359.22 mi.
2,760 mi = 4,441.92 kms