There are
1,644 mi
from Simi Valley, CA to Harlingen, TX
That's the driving distance. It would take 1 day 4 hours to go from Simi Valley, California to Harlingen, Texas.
The flight distance (direct flight from Simi Valley, CA to Harlingen, TX) is 1,373.34 mi.
1,644 mi = 1.61 kms