There are
1,788 mi
from Thornton, CO to Peekskill, NY
That's the driving distance. It would take 1 day 8 hours to go from Thornton, Colorado to Peekskill, New York.
The flight distance (direct flight from Thornton, CO to Peekskill, NY) is 1,623.77 mi.
1,788 mi = 1.61 kms