There are
1,202 mi
from Longmont, CO to Lathrop, CA
That's the driving distance. It would take 20 hours 30 mins to go from Longmont, Colorado to Lathrop, California.
The flight distance (direct flight from Longmont, CO to Lathrop, CA) is 882.26 mi.
1,202 mi = 1.61 kms