There are
1,965 mi
from Harlingen, TX to Walnut Creek, CA
That's the driving distance. It would take 1 day 10 hours to go from Harlingen, Texas to Walnut Creek, California.
The flight distance (direct flight from Harlingen, TX to Walnut Creek, CA) is 1,633.31 mi.
1,965 mi = 3,161.58 kms