There are
1,472 mi
from Great Falls, MT to Ballwin, MO
That's the driving distance. It would take 1 day 2 hours to go from Great Falls, Montana to Ballwin, Missouri.
The flight distance (direct flight from Great Falls, MT to Ballwin, MO) is 1,209.61 mi.
1,472 mi = 2,369.03 kms