One of the most arid spots in California, Saline Valley is a large area in the northern Mojave Desert. Three hot springs in the middle of the desert surrounded by palm trees offer a nice place to relax after a day of desert hiking and camping. A day trip to the springs is doable with an early start from one of the nearby towns (Big Pine, Lone Pine or Bishop), but most of the travellers prefer to stay overnight due to the long driving hours to and from the place.
Saline Valley was first known for its abandoned mines, but in the 1960s hot springs became popular among nudists, freethinkers, and other alternative groups who even had a semi-permanent camp in the desert. They've made several soaking pools of concrete, rock and tile, built showers, and even planted some grass areas.
When Saline Valley was included into Death Valley National Park, the camp was dispersed. You can get to the springs if you ask at the Big Pine station for directions, as they are not easily found on navigators. The best time to hike in Saline Valley is spring and fall, to avoid the winter storms, strong winds, and road closures of winter and the unbearable heat of summer. Whatever season you choose for the trip, make sure to bring lots of water and back up devices to call for help if necessary.