South Central United States in the context of "Texas-Mexico border"

The Southern United States (sometimes Dixie, also referred to as the Southern States, the American South, the Southland, Dixieland, or simply the South) is one of the four census regions defined by the United States Census Bureau. It is between the Atlantic Ocean and the Western United States, with the Midwestern and Northeastern United States to its north and the Gulf of Mexico and Mexico to its south.

Historically, the South was defined as all states south of the 18th-century Mason–Dixon line, the Ohio River, and the 36°30′ parallel. Within the South are different subregions such as the Southeast, South Central, Upper South, and Deep South. Maryland, Delaware, Washington, D.C., and Northern Virginia have become more culturally, economically, and politically aligned in certain aspects with the Northeastern United States and are sometimes identified as part of the Northeast or Mid-Atlantic. The U.S. Census Bureau continues to define all four places as formally being in the South. To account for cultural variations across the region, some scholars have proposed definitions of the South that do not coincide neatly with state boundaries. The South does not precisely correspond to the entire geographic south of the United States, but primarily includes the south-central and southeastern states. For example, California, which is geographically in the southwestern part of the country, is not considered part of the South; however, the geographically southeastern state of Georgia is.

Louisiana (French: Louisiane [lwizjan]; Spanish: Luisiana [lwiˈsjana]; Louisiana Creole: Lwizyàn) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25th in population, with roughly 4.6 million residents. Reflecting its French heritage, Louisiana is the only U.S. state with political subdivisions termed parishes, which are equivalent to counties, making it one of only two U.S. states not subdivided into counties (the other being Alaska and its boroughs). Baton Rouge is the state's capital, and New Orleans, a French Louisiana region, is its most populous city with a population of about 363,000 people. Louisiana has a coastline with the Gulf of Mexico to the south; a large part of its eastern boundary is demarcated by the Mississippi River and the mouth of the Mississippi or delta defines much of its lower topography.

Much of Louisiana's lands were formed from sediment washed down the Mississippi River, leaving enormous deltas and vast areas of coastal marsh and swamp. These contain a rich southern biota, including birds such as ibises and egrets, many species of tree frogs—such as the state-recognized American green tree frog—and fish such as sturgeon and paddlefish. More elevated areas, particularly in the north, contain a wide variety of ecosystems such as tallgrass prairie, longleaf pine forest and wet savannas; these support an exceptionally large number of plant species, including many species of terrestrial orchids and carnivorous plants. Over half the state is forested.

Oklahoma (/ˌoʊkləˈhoʊmə/ OH-klə-HOH-mə; Choctaw: Oklahumma, pronounced [oklahómma]) 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.

The state's name is derived from the Choctaw words okla, 'people' and humma, which translates as 'red'. Oklahoma is also known informally by its nickname, "The Sooner State", in reference to the Sooners, American settlers who staked their claims in formerly American Indian-owned lands until the Indian Appropriations Act of 1889 authorized the Land Rush of 1889 opening the land to settlement.

Oklahoma (/ˌoʊkləˈhoʊmə/ OH-klə-HOH-mə; Choctaw: Oklahumma, pronounced [oklahómma]) is a 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.

The state's name is derived from the Choctaw words okla, 'people' and humma, which translates as 'red'. Oklahoma is also known informally by its nickname, "The Sooner State", in reference to the Sooners, American settlers who staked their claims in formerly American Indian-owned lands until the Indian Appropriations Act of 1889 authorized the Land Rush of 1889 opening the land to settlement.