There are
1,822 mi
from San Marcos, CA to Farmington, MO
That's the driving distance. It would take 1 day 8 hours to go from San Marcos, California to Farmington, Missouri.
The flight distance (direct flight from San Marcos, CA to Farmington, MO) is 1,533.22 mi.
1,822 mi = 2,932.04 kms