Why did the settlers pour into the southeast subregion in the 1830s

The land was sparse, fertile, and the territory was mostly uninhabited.

The territory was fit for cotton production in an era when demand for it was increasing. Besides, land in the Upper South had been exhausted by the time, and the demand for tobacco, and rice, the two staple crops of the region, was dwindling.

All in all, there was great incentive for farmers from the eastern seabords and upper south to move to the new territories.