There are
1,835 mi
from St Charles, MO to Santee, CA
That's the driving distance. It would take 1 day 8 hours to go from St Charles, Missouri to Santee, California.
The flight distance (direct flight from St Charles, MO to Santee, CA) is 1,532.55 mi.
1,835 mi = 2,953.17 kms