There are
1,873 mi
from San Marcos, CA to Edwardsville, IL
That's the driving distance. It would take 1 day 8 hours to go from San Marcos, California to Edwardsville, Illinois.
The flight distance (direct flight from San Marcos, CA to Edwardsville, IL) is 1,564.75 mi.
1,873 mi = 1.61 kms