The Southwestern United States (also known as the American Southwest or simply the Southwest) is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah. Narrowly defined, the "core" Southwest is centered around the Four Corner states, with parts of the other states making up the beginnings and endings of the Southwest. The five main southwestern states; Arizona, New Mexico, Colorado, Utah, and Nevada are also all considered part of the Mountain West, as well as the southwest. The total population of these states is roughly 19 million people.
Most of it was a part of the Viceroyalty of New Spain, in the Spanish Empire, during the Modern Era. Land that is now California, Arizona, Nevada, Utah, New Mexico, Colorado, Wyoming, Oklahoma and Kansas was all part of Mexico before the Mexican-American War and the Gadsden Purchase of 1853. Portions of some of the areas in the "divided" states, and including western parts of Texas, were those in dispute after the Texas Revolution.
A butte/bjuːt/ is a conspicuous isolated hill with steep, often vertical sides and a small, relatively flat top; buttes are smaller than mesas, plateaus, and table landforms. In some regions, such as the north central and northwestern United States, the word is used for any hill. The word butte comes from a French word meaning "small hill"; its use is prevalent in the western United States, including the southwest, where "mesa" is also used. Because of their distinctive shapes, buttes are frequently landmarks in plains and mountainous areas.
In differentiating mesas and buttes, geographers use the rule that a mesa has a top wider than its height, while a butte's top is narrower. Three classic buttes are Scotts Bluff (actually a collection of five bluffs) in Nebraska, Crested Butte in Colorado, and Elephant Butte in New Mexico.
Among the well-known non-flat-topped buttes in the United States are Bear Butte, South Dakota, and Black Butte, Oregon. In many cases, buttes have been given other names that do not use the word butte, for example, Courthouse Rock, Nebraska. Also, some large hills that are technically not buttes have names using butte, an example of which is Kamiak Butte in Washington State.