There are
2,809 mi
from Rockville, MD to Pacifica, CA
That's the driving distance. It would take 2 days 1 hour to go from Rockville, Maryland to Pacifica, California.
The flight distance (direct flight from Rockville, MD to Pacifica, CA) is 2,432.85 mi.
2,809 mi = 4,520.09 kms