There are
2,764 mi
from Rockville, MD to Lompoc, CA
That's the driving distance. It would take 2 days 1 hour to go from Rockville, Maryland to Lompoc, California.
The flight distance (direct flight from Rockville, MD to Lompoc, CA) is 2,390.89 mi.
2,764 mi = 4,448.52 kms