Pursuant to a congressional request, GAO presented information on livestock grazing on public rangeland managed by the Bureau of Land Management, focusing on: (1) the number, average acreage, and average stocking rate of BLM allotments; and (2) the total and average number of animal unit months covered by grazing permits. GAO found that, as of September 1991: (1) BLM administered 22,058 allotments that encompassed 163.3 million acres in the 16 western states; (2) the average acreage of BLM allotments varied by state office, ranging from over 1,500 acres in Montana to over 56,500 acres in Nevada; (3) the 500 largest allotments encompassed over 76 million acres and the 500 smallest allotments encompassed about 13,000 acres; and (4) the average number of acres required to provide 1 animal unit month on BLM allotments ranged from over 20 acres in California and Nevada to fewer than 7 acres in Montana and New Mexico.