There are
2,044 mi
from St Charles, MO to Hayward, CA
That's the driving distance. It would take 1 day 11 hours to go from St Charles, Missouri to Hayward, California.
The flight distance (direct flight from St Charles, MO to Hayward, CA) is 1,706.68 mi.
2,044 mi = 3,290.05 kms