There are
1,835 mi
from La Mesa, CA to Festus, MO
That's the driving distance. It would take 1 day 8 hours to go from La Mesa, California to Festus, Missouri.
The flight distance (direct flight from La Mesa, CA to Festus, MO) is 1,538.67 mi.
1,835 mi = 2,952.75 kms