The Mendocino mule deer herd complex is comprised of three overlapping black-tailed deer (Odocoileus hemionus columbianus) administrative herds, including Mendocino, Clear Lake, and Alder Springs. Mendocino black-tailed deer exhibit variable movement patterns and strategies, including traditional seasonal migrants, full-time residents, and multi-range migrants. Migrants move between seasonal ranges from a multitude of lower elevation areas within the North Coast Range in winter to higher elevation summer ranges (fig. XXX). Local biologists predict high-use winter ranges throughout both foothill slopes and valley bottoms. Female deer of the Mendocino herd complex exhibit both short-term (seasonal/annual) and long-term (multi-generational) fidelity to their summer ranges (Bose and others, 2017). Population density estimates in 2011 and 2012 based on fecal DNA pellets indicated exceptionally high deer densities on productive summer ranges (50.75 deer/km2; Lounsberry and others, 2015). However, the population was declining strongly at the time of study due to low adult survival, including of prime-aged females (Marescot and others, 2015). Survival rates were lower than typically observed for mule deer populations across their range (Forrester and Wittmer, 2013). Predation from black bears (Ursus americanus) and coyotes (Canis latrans) was the primary cause for low annual survival of fawns (Forrester and Wittmer, 2019) while predation from pumas (Puma concolor) was the foremost cause of adult female mortality (Marescot and others, 2015), often in areas deemed less familiar to the individual mule deer (Forrester and others, 2015). Puma kill rates of mule deer in the study area were the highest reported across their range (Cristescu and others, 2022), likely due to high rates of kleptoparasitism from black bears (Elbroch and others, 2015; Allen and others, 2021). More recent research from CDFW was directed at the collection of DNA from fecal pellets to update population density estimates (CDFW, 2015) and to determine population response to catastrophic wildfire (CDFW, 2019; CAL FIRE, 2021). Habitat use of mule deer (Bose and others, 2018) and their predators (Cristescu and others, 2019) in the area is well understood and most of the habitats occupied by the Mendocino herd complex are protected and not at risk of development or fragmentation. However, the risk of catastrophic wildfire and climate changed induced landscape scale changes exist with the consequences unknown. These mapping layers show the location of the winter range for mule deer (Odocoileus hemionus) in the Mendocino population in California. They were developed from 65 winter sequences collected from a sample size of 45 animals comprising GPS locations collected every 1-13 hours.