The northernmost four (Parmer, Castro, Swisher, and Briscoe) also form part of the Texas Panhandle region.
The region consists of a portion of the Texas side of the geographical Llano Estacado and the western portion of the lower part of the Southwestern Tablelands ecological region. South Plains extends south of the Texas Panhandle, centered at Lubbock. While prominent in the area of petroleum production, the South Plains is mainly an agricultural region, producing a great percentage of the nation's cotton and possessing numerous large cattle ranches.[citation needed] The South Plains is also home to several colleges and universities, the largest being Texas Tech University in Lubbock.
Cotton is the most common crop grown in South Plains region. In 2004 and again in 2005, records were broken for cotton production.[1] In an extended area comprising 31 counties in and near the South Plains, more than a million bales of cotton were harvested in 2005. This makes the South Plains the world’s largest cotton-producing region.