There are
2,002 mi
from Harlingen, TX to Vacaville, CA
That's the driving distance. It would take 1 day 11 hours to go from Harlingen, Texas to Vacaville, California.
The flight distance (direct flight from Harlingen, TX to Vacaville, CA) is 1,641.66 mi.
2,002 mi = 3,222.01 kms