There are
254 mi
from Decatur, IL to Waukesha, WI
That's the driving distance. It would take 4 hours 53 mins to go from Decatur, Illinois to Waukesha, Wisconsin.
The flight distance (direct flight from Decatur, IL to Waukesha, WI) is 222.30 mi.
254 mi = 408.58 kms