or Staked Plain Plateau, southeastern New Mexico, western Texas, and northwestern Oklahoma in the U.S. Occupying an area of about 30,000 sq mi (78,000 sq km), it is a semiarid plain with occasional pools of rainwater. Its soil supports grazing, dryland farming of grains, and irrigated cotton production. Production of petroleum and natural gas is also important. Lubbock and Amarillo, Texas, are its most important cities