The data on new finds of the remains of Mammoth fauna mammals in the basin of Middle Lena River (Yakutia, the area of natural park “Lenskiye Stolby (Lena Pillars)” and adjacent territories) is represented in the article. Based on these data, the species composition of the mammoth fauna list of large mammalian species from this region was specified. 11 species of large mammals were identified, among which, for the first time for this region, the presence of a cave lion was established. A series of new radiocarbon datings allowing to note that mass burials of the Pleistocene mammalian remains were mainly formed in this region during the Karginian interstadial (60 (55)–24 thousand years ago, MIS-3). The obtained radiocarbon dates and species composition are consistent with the data that the Karginian interstadial was the most favorable for the distribution of the mammoth fauna in the territory of Yakutia. The results of the studies show that in the Late Pleistocene, the ecological preferences of Ovis nivicola differed from the modern ones. For the first time, the distribution of Panthera spelaea is revealed in the region of the middle reaches of the Lena River.