Southwestern United States

Regional definitions of the Southwestern United States vary from source to source. The states shown in dark red are usually included, and all or portions of the striped states may or may not be considered to be in the region.

The Southwestern United States (also called the American Southwest or simply the Southwest) is a portion of the United States that mostly considered located to be in the country's western region. It is warmer than the North and is drier than the East.

Depending on the source, the region almost always includes Arizona and New Mexico and at least parts of Southern California, Nevada, Utah, and Colorado, but it may also include the Trans-Pecos "horn" of the far west of Texas. California, Nevada, Utah and Colorado are also classified as in the "West" by the United States Census Bureau, which considers Texas and Oklahoma to be in the "South."

The Southwest is growing and has large cities like Phoenix, Las Vegas, El Paso, Albuquerque, and Tucson. It is one of the fastest growing parts of the country.

The Southwest used to be Santa Fe de Nuevo México and New Mexico Territory.