There are
1,396 mi
from Simi Valley, CA to Gainesville, TX
That's the driving distance. It would take 1 day to go from Simi Valley, California to Gainesville, Texas.
The flight distance (direct flight from Simi Valley, CA to Gainesville, TX) is 1,239.22 mi.
1,396 mi = 2,247.41 kms