Southwestern white pine (Pinus strobiformis; SWWP) is a conifer species that occurs at mid to high elevations in the mountains of Arizona, New Mexico, and northern Mexico. A key component of mixed conifer forests in the region, SWWP is an important species for wildlife and biodiversity. The dual threats of the non-native fungal pathogen that causes white pine blister rust (WPBR) and a warmer, drier projected future climate have created an uncertain future for SWWP. In this study, we used a novel multi-scale optimization approach including an ensemble of four species distribution modeling methods to explore the relationship between SWWP occurrence and environmental variables based on climate, soil, and topography. Spatial projections of these models reflecting the present climate provide an improved range map for this species that can be used to guide field data collection and monitoring of WPBR outbreaks. Future projections based on two emissions scenarios and an ensemble of 15 general circulation models project a large range shift and range contraction by 2080. Changes in the future distribution were particularly extreme under the higher emissions scenario, with a more than 1000 km northerly shift in the mean latitude and 500m increase in the mean elevation of the species' suitable habitat. This coincided with a range contraction of over 60% and a significant increase in habitat fragmentation. The ability of SWWP to realize its projected future range will depend on colonization at the leading edge of the range shift, including dispersal dynamics, resistance to WPBR, competition with other species, and genetic adaptations to local climate. Our results provide information that can be used to guide monitoring efforts and inform conservation planning for this keystone species.