Saguaros are endemic to the Sonoran Desert and are found only in western Sonora in Mexico and in southern Arizona in the US, although plants are occasionally found in southeastern California. Elevation is a limiting factor to its environment, as the saguaro is sensitive to extended frost or cold temperatures. No confirmed specimens of wild saguaros have been found anywhere in New Mexico, Texas, Colorado, Utah, or Nevada, nor in the high deserts of northern Arizona. The northern limits of their range are the Hualapai Mountains in Arizona. They are the northernmost columnar cacti in the Americas.: