There are
2,727 mi
from San Clemente, CA to Lansdowne, PA
That's the driving distance. It would take 2 days to go from San Clemente, California to Lansdowne, Pennsylvania.
The flight distance (direct flight from San Clemente, CA to Lansdowne, PA) is 2,366.12 mi.
2,727 mi = 4,387.88 kms