From Fodor’s online:

The accurately named Jumbo Rocks Campground is woven among the stacked and strewn oversized volcanic boulders unique to Joshua Tree National Park. Several hiking trails begin at Jumbo Rocks, a 126-campsite facility with vault toilets. During Joshua Tree’s peak season, October through May, hikers and rock-scramblers who reserve the campground well in advance are rewarded with views of the boulders whose colors shift throughout the day, from the morning sunrise to the fire’s glow. In the hot, dry summers, Jumbo Rocks is first-come, first-served.

For more information click on following link: https://www.nps.gov/jotr/planyourvisit/jumbo-rocks-campground.htm