The objectives of this study were to: l) determine the contribution of federal land grazing to beef production in Utah and the 11 western states, and 2) trace the impact of hypothetical incremental reductions in federal land grazing in the 11 western states on total beef supply and retail beef prices in the United States. The federal land animal units in the 11 western states were obtained from Bureau of Land Management and Forest Service records. The animal units were converted into the number of breeding cows and feeder calves totally dependent on federal land grazing, with the help of animal units per breeding cow. The animal units per breeding cow were calculated from a representative stock count chart of a typical 50 cow Utah ranch. The same chart provided percentage proportions of the number of calves and feeder calves. These feeder calves are the animals that originate and are totally dependent on federal lands. The minimum contribution of federal land grazing in the 11 western states to total beef supply in the United States ranges between dressed beef from feeder calves and cull cows on one end, and slaughter animals and cull cows on the other. The actual minimum contribution is somewhere to the middle of these extremes. The hypothetical incremental reductions in federal land grazing were calculated in terms of percentage reduction in the number of cows, calves and feeder calves, and the resultant decreases in beef tonnage on the lower and upper limits of minimum contribution of these lands to total beef supply in the United States. These reductions in beef supply were compared to total United States' beef supply and reductions in total beef supply were estimated in percentage. To estimate the economic and other impacts on individual ranchers, local communities and regional economy, the feed grain in corn equivalents and forage production were compared to livestock and poultry requirements in the 11 western states. It appears that Utah is deficient both in feed grain and roughage production as compared to requirements. The 11 western states as a group were surplus in 1974 in both feed grain and roughage production as compared to livestock and poultry requirements. The contribution of federal lands in roughage production was also estimated. The importance of federal rangelands' contribution, in my study is only 25 percent of total roughage production in the 11 western states and is discussed in the light of other benefits that would be lost if grazing were eliminated from federal lands. Lastly, the impact of reduction in federal grazing in the 11 western states on retail beef prices was estimated by using the concept of price elasticity of demand. It was concluded that an increasingly higher percentage increase in retail prices would occur for given percentage decreases in beef supply (by way of hypothetical incremental reduction in federal land grazing) for increasingly inelastic coefficients of elasticity.