There are
2,580 mi
from Rancho Cucamonga, CA to Rockville, MD
That's the driving distance. It would take 1 day 22 hours to go from Rancho Cucamonga, California to Rockville, Maryland.
The flight distance (direct flight from Rancho Cucamonga, CA to Rockville, MD) is 2,250.81 mi.
2,580 mi = 4,151.49 kms