There are
2,734 mi
from San Marcos, CA to Lansdowne, PA
That's the driving distance. It would take 2 days 1 hour to go from San Marcos, California to Lansdowne, Pennsylvania.
The flight distance (direct flight from San Marcos, CA to Lansdowne, PA) is 2,350.36 mi.
2,734 mi = 3.22 kms