South-western USA and Mexico, from California, Utah and Colorado eastern inland to Missouri and Louisiana, through coastal Texas and Baja California, south to Michoacan, Puebla and Veracruz.
 
Population
Estimated population is 1,100,000 (2010).
Greater Roadrunner (Geococcyx californianus) [XC254872]
by Richard E. Webster from Paradise Cemetery, Chiricahua Mountains, Cochise County, Arizona, United States (bill rattle (rapid series))
Greater Roadrunner (Geococcyx californianus) [XC254876]
by Richard E. Webster from Rodeo, Hidalgo County, New Mexico, United States (bill rattle)
Subspecies
Population from Texas (USA) south to Nuevo Leon and Veracruz (Mexico) averages smaller and has been described as subspecies dromicus, but birds from this region overlap in size with those in other parts of range.
No subspecies.
Similar Species
Like Lesser Roadrunner (Geococcyx velox) but underparts streaked.
References
See References.