Joshua Tree National Park comprises over 1,200 square miles of desert land in southern California. It was designated a U.S. National Monument in 1936 and was upgraded to a National Park in 1994. The western portion of the park is in the Mojave Desert, where the higher elevations make it perfect for the park's namesake Joshua Trees. The rocky terrain makes it a popular spot for rock climbing. The eastern part of the park is part of the Colorado Desert, looking much more like stereotypical desert with flatter terrain and significantly less vegetation.
There are nine campgrounds at Joshua Tree and they're the starting points for many of the park's hiking trails. It's possible to do some driving in the park, but most roads are unpaved and require a four-wheel-drive vehicle. The park is far enough from the bright lights - and pollution - of the big city that it's a popular place to engage in stargazing.
Joshua Tree National Park is about 130 miles east of downtown Los Angeles and 180 miles south of Las Vegas. The closest places with hotels are Twentynine Palms (on the north side of the park) and Indio (on the southwest).