There are
1,752 mi
from Harlingen, TX to Greenbelt, MD
That's the driving distance. It would take 1 day 8 hours to go from Harlingen, Texas to Greenbelt, Maryland.
The flight distance (direct flight from Harlingen, TX to Greenbelt, MD) is 1,494.75 mi.
1,752 mi = 2,819.92 kms