- The southwestern United States, including Arizona, New Mexico, Texas, and Utah, is home to a wide variety of cacti, including saguaro, prickly pear, and barrel cactus.
- The Sonoran Desert, located in Arizona and California, is home to many species of cacti, including the giant saguaro cactus, which is the largest cactus in the United States.
- The Mojave Desert, located in California, Nevada, and Arizona, is also home to a variety of cacti, including the Joshua tree and the barrel cactus.
- The Chihuahuan Desert, located in Texas, New Mexico, and Mexico, is home to many species of cacti, including the sotol and the ocotillo.
- The Great Basin Desert, located in Nevada, Utah, and Idaho, is home to several species of cacti, including the Great Basin barrel cactus and the beavertail cactus.