There are
1,276 mi
from Thornton, CO to St Clair Shores, MI
That's the driving distance. It would take 22 hours 48 mins to go from Thornton, Colorado to St Clair Shores, Michigan.
The flight distance (direct flight from Thornton, CO to St Clair Shores, MI) is 1,159.10 mi.
1,276 mi = 1.61 kms