There are
1,515 mi
from Thornton, CO to Simpsonville, SC
That's the driving distance. It would take 1 day 3 hours to go from Thornton, Colorado to Simpsonville, South Carolina.
The flight distance (direct flight from Thornton, CO to Simpsonville, SC) is 1,293.90 mi.
1,515 mi = 1.61 kms