The South Central United States or South Central states is a region of the United States located in the south central part of the country. It evolved out of the Old Southwest, which originally was literally the western U.S. South, as can be seen in the now defunct Southwest Conference of the NCAA. The states of Arkansas, Louisiana, Oklahoma, and Texas (which make up what the Census Bureau Division calls West South Central States) are almost always considered the "core" of the region. As part of the East South Central States sub-group of the Census Bureau classification, Alabama, Mississippi, Tennessee and Kentucky are also frequently listed under the heading. At the highest extent, Kansas, and Missouri, may be included by some sources. All or parts these states are in the Central Time Zone. At different and changing points in time, all of the above states were/are considered part of the West in American history.