Biodiverse areas marked by endemism and populations disjunct from main distributions are arguably conservation priorities because of their species diversity, genetic distinctiveness, and biogeographic significance. Through the glacial intervals of the Quaternary, ‘refugial’ areas for temperate tree species, inferred by paleorecords, were located hundreds to thousands of km from the ice sheets. Over the past two decades evidence has accumulated that, in addition to low-latitude refugia, mid- and high-latitude refugia existed that supported warm-adapted species. Such populations decrease the risk of extinction of species with low mobility that would otherwise be required to migrate long distances to areas with a suitable climate. Small isolated (cryptic) northern refugia would have served as important predispersed nuclei for postglacial range expansion. Indeed, population histories comprising of persistence through glacial periods and subsequent range expansion data may partly explain modern patterns of biodiversity from the Arctic to the tropics. How species persisted through the large climatic changes of the Pleistocene has been a long-standing focus of paleoecological research. However, because paleoecological archives are patchy, and potential refugia are small, holes remain in our understanding of the importance of northern refugia. Consequently, the historical record remains under-utilized to help reduce such uncertainties. Recently, phylogeography and distribution modeling have offered new insights unavailable from paleorecords. Reconstruction of Pleistocene refugia and migration routes should offer insights into how mountainous terrain may have buffered species populations through periods of significant climate change. This session will bring together researchers who work on historical reconstruction of populations from different disciplines and to assess the prospect for ‘best evidence syntheses’ to leverage the results from any one approach. The talks will include: 1) an introduction to the concept of climate relicts with a focus on patterns of endemism, 2) paleoecology studies from mountainous terrain, 3) phylogeography studies that support presence of refugia, and 4) mountain climatology and species distribution modeling including topographic influences on microclimates under present and past climates. This session addresses the need to identify and preserve Nature’s recent historical legacies. The convergence of bioinformatics of species distributions, new paleoecological data sets, and advanced methods in phylogeography and microclimatology allows for new syntheses highly relevant to biodiversity conservation. The Pacific Northwest is an excellent setting for this topic because textbook examples of northern refugia exist from the Olympic Mountains, northern Idaho, and Beringia.