There are
668 mi
from St Louis, MO to Seagoville, TX
That's the driving distance. It would take 12 hours 1 min to go from St Louis, Missouri to Seagoville, Texas.
The flight distance (direct flight from St Louis, MO to Seagoville, TX) is 545.45 mi.
668 mi = 1,075.02 kms