Roughly rectangular, Riverside County covers in Southern California, spanning from the greater Los Angeles area to the Arizona border. Geographically, the county is mostly desert in the central and eastern portions, but has a Mediterranean climate in the western portion. Most of Joshua Tree National Park is located in the county. The resort cities of Palm Springs, Palm Desert, Indian Wells, La Quinta, Rancho Mirage, and Desert Hot Springs are all located in the Coachella Valley region of central Riverside County.