The Mid-Columbia mule deer herd inhabits a highly variable landscape, featuring annual precipitation ranging from 112 inches (in; 285 cm) near Red Hill in the western part of this herd range to 14 in (36 cm) near The Dalles, Oregon, in the eastern part (National Oceanic and Atmospheric Administration, 2021). Mule deer wintering in the east usually occupy altered grassland and agricultural habitats interspersed with patches of basin big sagebrush, nonnative annual grasses, and both native and planted grassland (Conservation Reserve Program fields). Most of these mule deer are nonmigratory and reside year round near Fifteenmile Creek, Eightmile Creek, and Deschutes River. The mule deer that do migrate travel south to similar types of vegetation near Summit Ridge. Habitats to the west, however, contain more forested cover and winter ranges primarily feature a combination of grasslands, Purshia tridentata (antelope bitterbrush), oak, ponderosa pine, and mixed-conifer forest. Mule deer in the western region are more migratory, containing individuals that travel west to the foothills of Fir Mountain, Lookout Mountain, and Mount Hood in spring. Summer ranges are dominated by mixed-conifer forests featuring pacific silver fir, mountain hemlock, T. heterophylla (western hemlock), and Pseudotsuga menziesii (Douglas fir). Pastures and farmland are prevalent in the east where dryland wheat, alfalfa hay, and cherries are economically important crops. Black-tailed deer co-occur with mule deer west of U.S. Highway 197 and the two can hybridize in this area. Along with frequent smaller wildfires, in 2018, the South Valley Road fire burned 20,026 acres (8,104 ha) of winter habitat near U.S. Highway 197, and the Substation and the Long Hollow fires scorched a combined 111,881 acres (45,277 ha) along the northern portion of the Deschutes River (BLM, 2023a). The 2020 White River fire and 2022 Miller Road fire also respectively burned 17,405 acres (7,044 ha) and 10,847 acres (4,390 ha) of seasonal range and migration corridor habitat outside of Pine Grove, Oregon. Depending on location, these large fires can have positive or negative impacts on the Mid-Columbia mule deer herd. In the east, fires reduce shelter and allow invasive grasses to proliferate in habitats lacking perennial plant cover, but in the west, they can beneficially open canopy cover in heavily forested areas, exposing the understory to sunlight and invigorating valuable forage species. These mapping layers show the location of the winter ranges for mule deer (Odocoileus hemionus) in the Mid-Columbia population in Oregon. They were developed from 232 winter sequences collected from a sample size of 82 animals comprising GPS locations collected every 5-13 hours.