There are
1,904 mi
from St Charles, MO to Grass Valley, CA
That's the driving distance. It would take 1 day 8 hours to go from St Charles, Missouri to Grass Valley, California.
The flight distance (direct flight from St Charles, MO to Grass Valley, CA) is 1,632.71 mi.
1,904 mi = 3,064.89 kms