There are
1,767 mi
from Rockville, MD to Hidalgo, TX
That's the driving distance. It would take 1 day 8 hours to go from Rockville, Maryland to Hidalgo, Texas.
The flight distance (direct flight from Rockville, MD to Hidalgo, TX) is 1,515.08 mi.
1,767 mi = 2,843.90 kms