There are
1,167 mi
from Longmont, CO to Seymour, IN
That's the driving distance. It would take 20 hours 51 mins to go from Longmont, Colorado to Seymour, Indiana.
The flight distance (direct flight from Longmont, CO to Seymour, IN) is 1,024.71 mi.
1,167 mi = 1.61 kms