This park is located on the southern edge of the Mojave desert. It is a very large park consisting mostly of rocky, very arid, rolling hills. Typical cacti found here are: Cylindorpuntia acanthocarpa, Cylindropuntia Echinocarpa, Cylindropuntia Bigelovii, Echinocereus engelmannii, Opuntia Basilaris, Ferocactus cylindraceus, Mammillaria Dioca, Mammillaria Tetrancistra, and Escobaria Vivipara

The second largest national park in the 48 contiguous states is Joshua Tree. Half of the park is located in the Mojave Desert and half in the Colorado Desert. One can easily witness the transition from one desert to the other while driving through the park. Visitors can be sure to see these cacti species: Cylindropuntia bigelovii, Cylindropuntia ramosissima, Cylindropuntia echinocarpa, Echinocereus engelmannii, Echinocereus mojavensis, Escobaria vivipara, Ferocactus cylindraceus, and Opuntia basilaris.

Located in the very heart of the Sonoran Desert and on the US-Mexico border, Organ Pipe Cactus National Monument boasts cacti that can be found no where else in the United States. This park also features remote one-way drive dirt roads that wind through the desert like a hiking trail, offering an intimate desert visit for everyone. Cacti found here are: Carnegia gigantea, Cylindropuntia arbuscula, Cylindropuntia bigelovii, Cylindropuntia fulgida, Cylindropuntia leptocaulis, Cylindropuntia spinosior, Cylindropuntia versicolor, Echinocereus engelmannii, Ferocactus wislizeni, Grusonia emoryi, Mammillaria grahamii, Opuntia engelmannii, Opuntia macrocentra, Pachycereus schottii, and Stenocereus thurberi.

Saguaro National Park is named after the most well-known cacti in the world; the Giant Saguaro (Carnegia gigantea). It is broken up into 2 units, an East and a West. Part of the Sonoran Desert, cacti grow here prolifically. Species that can be found here are: Carnegia gigantea, Cylindropuntia arbuscula, Cylindropuntia bigelovii, Cylindropuntia fulgida, Cylindropuntia leptocaulis, Cylindropuntia spinosior, Cylindropuntia versicolor, Echinocereus engelmannii, Ferocactus wislizeni, Mammillaria grahamii, Opuntia engelmannii, Opuntia macrocentra, and Peniocereus greggii.