There are
945 mi
from Thornton, CO to Waunakee, WI
That's the driving distance. It would take 17 hours 14 mins to go from Thornton, Colorado to Waunakee, Wisconsin.
The flight distance (direct flight from Thornton, CO to Waunakee, WI) is 833.37 mi.
945 mi = 1,521.00 kms