Joshua Tree National Park contains two deserts. The Colorado Desert occupys the lower part of the park and contains cholla cactus. The higher, moister, and slightly cooler Mojave Desert is the special habitat of the undisciplined-looking Joshua tree.

Joshua Tree National Park received its name from the Mormon pioneers who crossed the desert and after encountering the desert tree they named it after the Biblical prophet Joshua. The tree's crooked limbs reminded them of Joshua arms raised toward Heaven. Some climbers and photographers believe Joshua Tree National Park is Heaven on earth.