Denisova Cave (, also Ayu-Tash) is a cave in the Bashelaksky Range of the Altai mountains, Siberia, Russia. The cave is of great paleoarchaeological and paleontological interest. Bone fragments of the Denisova hominin, sometimes called the "X woman" (referring to the maternal descent of mitochondrial DNA) originate from the cave, including artifacts dated to ~40,000 BP. The cave is located in a region thought to have been inhabited concurrently in the past by Neanderthals and modern humans.