There are
847 mi
from Thornton, CO to Keokuk, IA
That's the driving distance. It would take 15 hours 5 mins to go from Thornton, Colorado to Keokuk, Iowa.
The flight distance (direct flight from Thornton, CO to Keokuk, IA) is 717.46 mi.
847 mi = 1,363.35 kms