There are
2,766 mi
from San Mateo, CA to Hagerstown, MD
That's the driving distance. It would take 2 days to go from San Mateo, California to Hagerstown, Maryland.
The flight distance (direct flight from San Mateo, CA to Hagerstown, MD) is 2,387.98 mi.
2,766 mi = 3.22 kms