There are
2,815 mi
from Gaithersburg, MD to Redwood City, CA
That's the driving distance. It would take 2 days 1 hour to go from Gaithersburg, Maryland to Redwood City, California.
The flight distance (direct flight from Gaithersburg, MD to Redwood City, CA) is 2,418.86 mi.
2,815 mi = 4,529.58 kms