Miles between Thornton, CO and Spencer, IA

There are
664 mi
from Thornton, CO to Spencer, IA

That's the driving distance. It would take 12 hours 34 mins to go from Thornton, Colorado to Spencer, Iowa.

The flight distance (direct flight from Thornton, CO to Spencer, IA) is 556.18 mi.

664 mi = 1,068.81 kms