There are
1,401 mi
from Simi Valley, CA to Gainesville, TX
That's the driving distance. It would take 1 day 1 hour 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.
1,401 mi = 1.61 kms