There are
2,062 mi
from Harlingen, TX to Clearlake, CA
That's the driving distance. It would take 1 day 12 hours to go from Harlingen, Texas to Clearlake, California.
The flight distance (direct flight from Harlingen, TX to Clearlake, CA) is 1,689.94 mi.
2,062 mi = 3,318.14 kms