There are
2,773 mi
from Rockville, MD to Clearlake, CA
That's the driving distance. It would take 2 days 1 hour to go from Rockville, Maryland to Clearlake, California.
The flight distance (direct flight from Rockville, MD to Clearlake, CA) is 2,414.69 mi.
2,773 mi = 4,462.28 kms