Joshua Tree National Park was declared a U.S. National Park in 1994 when congress passed the California Desert Protection Act. It had been a U.S. National Monument since 1936. The National Park covers a land area of 790,636 acres, an area slightly larger than the state of Rhode Island. The park includes parts of two deserts, each an ecosystem whose characteristics are determined primarily by elevation: the higher Mojave Desert and lower Colorado Desert.

The Joshua Tree is native to California, Arizona, Utah and Nevada, confined mostly to the Mojave Desert between 1,300 and 5,900 ft elevation. The name was given by Mormon settlers - the tree's unique shape reminded them of a Biblical story in which Joshua reaches his hands up to the sky in prayer. Ranchers and miners who were contemporary with the Mormon settlers used the trunks and branches as fencing and for fuel for ore-processing steam engines.

This tree has a top-heavy branch system, but also has what has been described as a "deep and extensive" root system, with roots reaching up to 36 feet. If it can survive the rigors of the desert, it can live for hundreds of years, up to a thousand years. The tallest trees reach 49 feet. Unfortunately, they are predicted to be severely affected by climate change. There is concern that they will be eliminated from Joshua Tree National Park and that this will fundamentally damage the ecosystem of the area. The trees may also have difficulty migrating to more favorable climates due to the extinction of the giant Shasta ground sloth 13,000 years ago; ground sloth dung has been found to contain Joshua Tree leaves, fruits, and seeds, suggesting that the sloths might have been key to the tree's dispersal.

The west (Joshua Tree) and north (Twentynine Palms) entrances are both on Highway 62.
During busy times, using the north entrance is worth the extra driving to avoid long lines.