There are
1,816 mi
from Great Falls, MT to Seabrook, TX
That's the driving distance. It would take 1 day 8 hours to go from Great Falls, Montana to Seabrook, Texas.
The flight distance (direct flight from Great Falls, MT to Seabrook, TX) is 1,512.98 mi.
1,816 mi = 2,923.03 kms