depends on whom you ask...we call where I live, west Texas. Geographically, however, it is central.
The canyon pictures are from Palo Duro Canyon which is near Amarillo in the Pan Handle. Some of the others are from the big ranches couple of hundred miles north of me around Lubbock and back to the west. Some may be further west toward El Paso as there is some very rugged country out that way.