McCabe and McCabe's 1984 estimate, graph above, is the most commonly cited estimate for historic deer populations.
VerCauteren, Kurt C., "The Deer Boom: Discussions on Population Growth and Range Expansion of -Tailed Deer" (2003). USDA National Wildlife Research Center - Staff Publications. 281. Page 16.
VerCauteren notes that "since the inception of modern wildlife management and modern bowhunting, about 1930 to present, whitetails do appear to have expanded their range." p. 15 and "In the lifetime of the last two or three generations of hunters, whitetails have expanded their range and increased in density across the western United States and the prairie of southern Canada, in most cases moving up vegetated river drainages that provided them cover." p. 17
VerCauteren's 2003 estimate (graph above) follows the McCabe and McCabe (1984) model, smoothing out the uptick in the mid-1800s, and adding estimated population into the year 2000, showing the pre-European settlement deer numbers are about the same as in the year 2000.
Some recent estimates are higher: Recent University of Wyoming research puts the white-tailed deer population for North America prior to European settlement at 30 to 40 million in Kauffman, M.J., J.E. Meacham, H. Sawyer, A.Y. Steingisser, W.J. Rudd, and E. Ostlind, editors. 2018. Wild Migrations: Atlas of Woming's Ungulutes. Oregon State University Press, Corvallis, Oregon. p. 28.
Graph above from Kip P. Adams and R. Joseph Hamilton. (2011). Management History. In Biology and Management of White-tailed Deer (p. 355). CRC Press.
Adams and Hamilton (2011) add some speculation on the pre-1500s population of the McCabe and McCabe model, explaining: "“McCabe and McCabe’s (1984) estimate suggests deer populations during this phase were substantial. If we assume an extremely aggressive removal rate of 50% of the standing population, McCabe and McCabe’s estimated harvest suggests a minimum standing population of 9–13 million whitetails. However, removing a third of the herd is a more realistic sustainable harvest rate, and suggests a deer population of 9–19 million deer. [p. 356]” Note that the lower bound, 9 million, should change as the removal rate changes - not in their analysis
In the current U.S. environment with many fewer large predators but more vehicles, hunters take about 19 percent of the population each year. In California where there is an unregulated mountain lion population, some bears, lots of coyotes, and vehicles instead of wolves, hunters take about 7 percent of the population each year. Adams and Hamilton's assumption of removing one third of the herd each year would leave few deer for the many mountain lions, wolves, and bears at the time. Their estimate would be much higher if modern percentages were applied.
Their explanation for the big population increase around 1500: “after Columbus as a result of disease, and estimates the human population declined by 20% from Columbus’ arrival to the mid-1600s. Some species, including whitetails, may have benefited from reduced Native American populations. Native Americans routinely relied on the whitetail resource (Halls, 1978; McCabe and McCabe, 1997, 1984; McDonald and Miller, 2004), and reduced harvest pressure could have allowed deer populations to experience an “ecological release” and increase in size. Thus, deer populations may have increased by around 1500 …” Their graph shows a doubling of the deer population over a few decades as a result of a 20% decline in the Native Amercian population - the proportions don't match in this analysis and the decline of Native Americans was over a much longer period.
USDA White-tailed Population Estimate 1975 to 2010
Source: Wildlife Population and Harvest Trends in the United States: A Technical Document Supporting the Forest Service 2010 RPA Assessment. Curtis H. Flather, Michael S. Knowles, Martin F. Jones, and Carol Schilli
The graph below is based on a response of 29 states, but indicates a recent peak in the deer population around the year 2000, consistent with the data collected on this site although showing a more modest decline from 2000 into 2010.
Blacktail and Mule Deer
Population Estimates: 10,000,000 elk pre-European colonization. A low population estimate of 100,000 in 1900. Current estimate of 1,000,000 (around 2018).