There are
1,937 mi
from Great Falls, MT to Weslaco, TX
That's the driving distance. It would take 1 day 10 hours to go from Great Falls, Montana to Weslaco, Texas.
The flight distance (direct flight from Great Falls, MT to Weslaco, TX) is 1,642.61 mi.
1,937 mi = 3,116.74 kms