There are
1,838 mi
from Costa Mesa, CA to Cahokia, IL
That's the driving distance. It would take 1 day 7 hours to go from Costa Mesa, California to Cahokia, Illinois.
The flight distance (direct flight from Costa Mesa, CA to Cahokia, IL) is 1,578.51 mi.
1,838 mi = 2,957.52 kms