There are
1,474 mi
from Thornton, CO to Dunkirk, NY
That's the driving distance. It would take 1 day 2 hours to go from Thornton, Colorado to Dunkirk, New York.
The flight distance (direct flight from Thornton, CO to Dunkirk, NY) is 1,340.33 mi.
1,474 mi = 1.61 kms