The Modoc Interstate mule deer (Odocoileus hemionus) herd migrates from a winter range near Clear Lake Reservoir in Modoc County, California north into Oregon in Klamath and Lake counties for the summer. Much of this herd likely resides in Oregon year-round as California population estimates (2000-3000) are lower than Oregon estimates (~15,000). Female mule deer were captured in Modoc in February 2017 and equipped with satellite collars manufactured by Lotek. Additional GPS data was collected between 1999-2001 from deer captured in 1999, and was included to supplement the small sample size of the 2017-2020 dataset. The data was collected with a priority to ascertain general distributions, survival, and home range, and not to model migration routes, hence the low sample sizes. Threats to this herd include increased fire frequency and conversion to non-native annual grass. Moreover, increased juniper woodlands has resulted in a loss of forbs, grass, and shrubs. These data provide the location of winter ranges for mule deerin the Modoc Interstate population in California and Oregon. They were developed from 32 winter sequences collected from a sample size of 20 animals comprising GPS locations collected every 8-12 hours.