The East Tehama herd is the largest migratory population of mule deer in California (Hill and Figura, 2020). Population numbers peaked in the 1960s, but have declined in recent decades (Ramsey and others, 1981; California Department of Fish and Wildlife unpublished data). These mule deer migrate from a lower elevation winter range in the foothills east of the Sacramento Valley to upper elevation summer ranges in the southern Cascades and northern Sierra Nevada. Although portions of the herd winter on the California Department of Fish and Wildlife’s Tehama Wildlife Area and other public lands, the winter range also comprises many private ranchlands. The herd’s summer range includes significant portions of Lassen National Forest as well as Lassen Volcanic National Park and private timberlands. Primarily oak woodlands and annual grasslands characterize the winter range, while the summer range consists of conifer forests, montane meadows, and montane chaparral. Potential threats to the herd include habitat changes resulting from fire management (including fire suppression and catastrophic wildfires), forest succession, vegetation management, and climate change. A small percentage of the herd are residents, inhabiting areas along the Sacramento River and areas of irrigated agriculture. These mapping layers show the location of the winter ranges for mule deer (Odocoileus hemionus) in the East Tehama population in California. They were developed from 36 sequences collected from a sample size of 33 animals comprising GPS locations collected every 1-23 hours.