There are
1,840 mi
from St Charles, MO to Oceanside, CA
That's the driving distance. It would take 1 day 8 hours to go from St Charles, Missouri to Oceanside, California.
The flight distance (direct flight from St Charles, MO to Oceanside, CA) is 1,544.71 mi.
1,840 mi = 2,961.96 kms