Texas's Osage Plains comprises of desert and mountains.
Osage Plains . The Osage Plains , covering west-central Missouri , the southeastern third of Kansas , most of central Oklahoma , and extending into north-central Texas , is the southernmost of three tallgrass prairie physiographic areas . Texas . Traveling from east to west , one can observe terrain that ranges from coastal swamps and piney woods , to rolling plains and rugged hills , and finally the desert and mountains of the Big Bend .