Crystal Cave is a marble karst cave within Sequoia National Park, in the western Sierra Nevada of California. It is one of at least 240 known caves in Sequoia National Park. Crystal Cave is in the Giant Forest area, between the Ash Mountain entrance of the park and the Giant Forest museum.The cave is a constant 48F. It is accessible by Park Service guided tours only. Tickets are not sold on-site, but must be bought at the Foothills or Lodgepole Visitor Center.