There are
2,787 mi
from Rockville, MD to Petaluma, CA
That's the driving distance. It would take 2 days to go from Rockville, Maryland to Petaluma, California.
The flight distance (direct flight from Rockville, MD to Petaluma, CA) is 2,428.65 mi.
2,787 mi = 4,485.20 kms