There are about 500 campsites within nine campgrounds inside Joshua Tree National Park. That sounds like a lot. However, they fill up quickly during peak season (October through May) and are available only on a first-come, first-serve basis. A favorite is the Hidden Valley Campground where 45 sites are available. Campers are required to pay a small fee in addition to the cost of admission to the park. The maximum stay is two weeks. Expect it to get cold at night but the star gazing is spectacular.