Native trout are culturally and ecologically important, but also likely to undergo widespread declines as the coldwater environments they require continue to shrink in association with global warming. Much can be done to preserve these fish but efficient planning and targeting of conservations resources has been hindered by a lack of broad-scale datasets and precise information about which streams are most likely to support native trout populations later this century. Using accurate stream temperature climate scenarios developed in the NorWeST project, we identify stream habitats for native Cutthroat Trout Oncorhynchus clarkii and Bull Trout Salvelinus confluentus across northern Idaho and northwestern Montana that are cold enough to serve as climate refugia and resist invasions by nonnative trout. Climate-safe coldwater habitats for Cutthroat Trout in the historical scenario encompassed 7,547 – 16,821 stream kilometers (depending on the local co-occurrence of Brook Trout Salvelinus fontinalis) and 12,189 kilometers for Bull Trout. The majority of coldwater habitats (77%-88%) currently occur on federal lands, a pattern that will become even more pronounced late in the century if the projected 63%-82% declines in coldwater habitats occur. The information developed for this project, and accompanying geospatial databases, are also available for a much larger area across the northwest U.S. to assist managers in strategic decision making about where to allocate conservation resources to best preserve native trout.