Six new species of Pachybrachis Chevrolat from the southwestern United States are described. Pachybrachis ashfork Barney, new species, Pachybrachis ephedra Barney, new species, Pachybrachis huachuca Barney, new species, Pachybrachis hurricane Barney, new species, Pachybrachis saguaro Barney, new species, and Pachybrachis texasensis Barney, new species are similar in appearance to several other species that are large, without ocular lines, with enlarged front tarsal claws, and have aedeagal median lobes with wisps and keels: Pachybrachis chaoticus Fall, Pachybrachis crassus Bowditch, Pachybrachis cylindricus Bowditch, Pachybrachis hybridus Suffrian, Pachybrachis peninsularis Fall, Pachybrachis pinguescens Fall, and Pachybrachis turgidicollis Fall. Descriptions, figures, and range maps are presented for each species.