There are
1,825 mi
from Buena Park, CA to St Charles, MO
That's the driving distance. It would take 1 day 7 hours to go from Buena Park, California to St Charles, Missouri.
The flight distance (direct flight from Buena Park, CA to St Charles, MO) is 1,561.02 mi.
1,825 mi = 2,936.74 kms