There are
1,798 mi
from Great Falls, MT to Pasadena, TX
That's the driving distance. It would take 1 day 7 hours to go from Great Falls, Montana to Pasadena, Texas.
The flight distance (direct flight from Great Falls, MT to Pasadena, TX) is 1,499.83 mi.
1,798 mi = 2,893.59 kms