The Gila Monster, Heloderma suspectum occurs from extreme southwest Utah to southern Sonora and northern Sinaloa; extreme southwest New Mexico to southern Nevada and just into California.
The northern form is the Banded gila monster and the southern form is the Reticulate gila monster.
Heloderma suspectum occurs up to an elevation of 1500 meters (4900 ft.). It has been observed to be more common in the wetter, rockier paloverde-sequaro desert scrub association than the drier, sandier creosote bush-bersage association. Heloderma suspectum also seem to prefer rocky foothills and avoid open flats and agricultural areas.