There are
922 mi
from Longmont, CO to Lake Havasu City, AZ
That's the driving distance. It would take 16 hours 17 mins to go from Longmont, Colorado to Lake Havasu City, Arizona.
The flight distance (direct flight from Longmont, CO to Lake Havasu City, AZ) is 640.34 mi.
922 mi = 1,484.36 kms