In the Northern Snake Range of Nevada, 20 packrat (Neotoma sp.) middens have been collected for use in palaeoecological reconstruction of the late Pleistocene and early Holocene. Samples from this region bring the palaeoecological record back to 38,00014C yr BP are being used to understand how mesic and xeric plants have migrated in response to environmental changes. Packrat middens contain assemblages of plant macrofossils, most of which are identifiable to species. Bristlecone pine (Pinus longaeva) is a midden species of interest due to its narrow climate envelope today. In the Great Basin, Bristlecone pine is most abundant above 3000m in porous, limestone soils. Midden macrofossils identify the range of bristlecone pine in the late Pleistocene and early Holocene down to 2000m, indicating environmentally dependent migration of Bristlecone during this period of rapid environmental change. Multiple middens from the area contain Bristlecone pine, with dates ranging from 32,00014C yr BP to 11,00014C yr BP. Some modern middens also contain Bristlecone due to cliffside microclimates where the tree can still compete for survival. Specimens from earlier time periods show that Bristlecone was much more abundant in number in lower elevation bands than today. These changes in Bristlecone habitat may also provide a platform for understanding the migration of other tree species in the face of anthropogenic climate change.