South Central United States

Arkansas (, ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma to the west. Its name derives from the Osage language, and refers to their relatives, the Quapaw people. The state's diverse geography ranges from the mountainous regions of the Ozark and Ouachita Mountains, which make up the U.S. Interior Highlands, to the densely forested land in the south known as the Arkansas Timberlands, to the eastern lowlands along the Miss

Oklahoma ( ; Choctaw: , ) is a landlocked state in the South Central and Southwestern region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northeast, Arkansas to the southeast, New Mexico to the west, and Colorado to the northwest. Partially in the western extreme of the Upland South, it is the 20th-most extensive and the 28th-most populous of the 50 United States. Its residents are known as Oklahomans and its capital and largest city is Oklahoma City.

U.S. Census Bureau region

ecoregion in Texas, Oklahoma, and Kansas