There are
1,590 mi
from Harlingen, TX to Duarte, CA
That's the driving distance. It would take 1 day 3 hours to go from Harlingen, Texas to Duarte, California.
The flight distance (direct flight from Harlingen, TX to Duarte, CA) is 1,326.93 mi.
1,590 mi = 2,559.17 kms