The Grizzly Flat herd winters in the western foothills of the Sierra Nevada near Grizzly Flats, California. The winter range includes conifer, vineyards, and oak woodland that is shared with a resident portion of the herd on a mix of private and public lands. In the spring, the Grizzly Flat herd migrates east to higher elevation terrain in the El Dorado National Forest, staying south of Interstate 50 and primarily north of U.S. Highway 88, to the crest of the Sierra Nevada. The summer range contains primarily mixed conifer opening up to high alpine granite near the crest of the Sierra Nevada. Although the population size of the Grizzly Flat herd is unknown due to limited surveys, it is considered stable to declining, affected primarily by dense overstory, environmental stressors, and habitat loss. This GPS collaring project was designed as part of a region-wide effort to obtain abundance estimates for deer using fecal DNA and home range analyses, with pinpointing migration routes and identifying winter ranges a secondary priority. Due to the small sample size of GPS-tagged mule deer, additional migration routes and winter ranges probably exist beyond the extent of our model output. These mapping layers show the location of the winter ranges for mule deer (Odocoileus hemionus) in the Grizzly Flat population in California. They were developed from 8 sequences collected from a sample size of 5 animals comprising GPS locations collected every 1-13 hours.