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In Montana, economic efficiency of cattle production is threatened by high feed and input costs. Dormant season livestock grazing reduces reliance on harvested feeds, but typically requires protein supplementation to be successful during periods of low forage quality. Providing supplements to grazing beef cattle during times of low forage quality may improve animal performance and vegetation utilization across the landscape. However, information relating supplementation strategies to individual grazing behavior and resource utilization on dormant forage is lacking. Thus, the intent of this research is to examine cattle resource utilization and residual cover and biomass removal of vegetation on rangelands grazed during the dormant season under two supplementation management strategies. Approximately 100 weaned composite heifer calves were randomly selected and placed into one of two supplementation treatments in each of 2 years (50 heifers/treatment/year); one receiving a free access 62% crude protein self-fed mineral/protein concentrate, and the other receiving a daily hand-fed 20% crude protein cake fed in bulk. Grazing for both treatments occurred simultaneously beginning in December (2015 & 2016) and continued through March (2016 & 2017). Thirty transects were randomly located within each pasture for measuring vegetation composition, production and quality, canopy cover and visual obstruction pre- and post-grazing. Grazing locations were recorded for twenty-one randomly selected individuals within each treatment with Lotek GPS collars containing head position sensors that record daily space use as well as timing and location of grazing activities at 5 minute intervals. Data sets were used to quantify space use as a continuous, probabilistic variable and related to the habitat covariates using generalized linear models to assess cattle resource utilization. Our research addresses comprehensive agro-ecosystem responses of dormant season cattle grazing and protein supplementation while providing multidimensional insight to stakeholders concerning grazing behavior and the ecological impacts of late season use on Montana rangelands.