One of these formed a crescent across south-central Alabama, with its western horn reaching up the Tombigbee River into northeastern Mississippi.

Its soil of loose black loam was partly forested, partly open, and densely matted with grass and weeds except where limestone cropped out on the hill crests and where prodigious cane brakes choked the valleys.

The area was locally known as the prairies or the black belt.[6] The process of opening it for settlement was begun by Andrew Jackson's defeat of the Creeks in 1814 but was not completed until some twenty years afterward.

The other and greater tract extended along both sides of the Mississippi River from northern Tennessee and Arkansas to the mouth of the Red River.

It comprised the broad alluvial bottoms, together with occasional hill districts of rich loam, especially notable among the latter of which were those lying about Natchez and Vicksburg.