Name all the states in the southwest region?

The core definition includes all of Arizona, the western portion of New Mexico, bordered on the east by the Llano Estacado, the southern portions of Colorado and Utah below the 39th parallel, the "horn" of Texas (the Trans-Pecos section, below New Mexico, which includes El Paso), the southernmost triangle of Nevada, and the very most southeastern portion of California, which encompasses the Mojave and Colorado Deserts.