Sagebrush ecosystems and wildlife that depend on them are under pressure from development, changing climate, as well as natural and human-caused disturbance. Mule deer (Odocoileus hemionus) are of particular concern due to population declines across many western states. We initiated a study to evaluate landscape-level changes ( disturbances, habitat treatments, development, and climate change) in Wyoming. This dataset contains age ratios (the number of juveniles to adult female mule deer) for 36 herd units in Wyoming, USA from 1985-2019. Age ratios provide a consistent metric of population demographics, including an index of recruitment (survival rate of young), which can be a sensitive metric of population change. The dataset includes annual summaries of environmental attributes within each mule deer herd unit's winter use area. Attributes fall into 6 categories: forage availability, habitat composition, predation, winter severity, energy development, and disturbances from wildfire and habitat treatments.