There are
388 mi
from St Charles, MO to Oconomowoc, WI
That's the driving distance. It would take 7 hours 21 mins to go from St Charles, Missouri to Oconomowoc, Wisconsin.
The flight distance (direct flight from St Charles, MO to Oconomowoc, WI) is 316.59 mi.
388 mi = 624.01 kms