There are
1,730 mi
from Great Falls, MT to Brenham, TX
That's the driving distance. It would take 1 day 6 hours to go from Great Falls, Montana to Brenham, Texas.
The flight distance (direct flight from Great Falls, MT to Brenham, TX) is 1,435.87 mi.
1,730 mi = 2,784.58 kms