There are
1,557 mi
from Great Falls, MT to Mesquite, TX
That's the driving distance. It would take 1 day 3 hours to go from Great Falls, Montana to Mesquite, Texas.
The flight distance (direct flight from Great Falls, MT to Mesquite, TX) is 1,275.77 mi.
1,557 mi = 2,506.00 kms