There are
1,433 mi
from Harlingen, TX to Mt Prospect, IL
That's the driving distance. It would take 1 day 2 hours to go from Harlingen, Texas to Mt Prospect, Illinois.
The flight distance (direct flight from Harlingen, TX to Mt Prospect, IL) is 1,228.72 mi.
1,433 mi = 2,306.52 kms