Illinois data:  Based on hunting data and comments from the state some estimates reported in the press, the deer population has been approximately stable from 2013 to 2021 in the 640,000 to 690,000 range.  In 2022 the state reported that a majority of counties are near or below their deer population goals.  The deer kill in the 2022-23 season increased in part because 16 northern Illinois counties were open to a special chronic wasting disease season and there was a late winter season in 24 mostly central and western counties.

The chart estimating the deer population relies on hunting data (adjusted for number of hunters) and population estimates reported in the press for 2004, 2008, 2009, 2012, and 2017.  The data.

About 640,000 deer in 2021, down from about 690,000 in 2020.  Some of the increase in the deer harvest in 2020 was attributed to increased hunting during the pandemic.

Deer populations in 2021 were thought to be stable to slightly increasing in a few regions, but hunting data indicates an overall decline from 2020.  In a 2021 survey most hunters reported seeing fewer deer over the past five years.  Good weather in 2020 supported populations.  In 2020 the state changed hunting regulations to increase the deer population in three counties and reduce the population in 20 counties.  An estimated 660,000 deer in 2019, and 652,000 for 2018 based on hunting data.   In 2018 antlerless restrictions for east-central counties were implemented to grow the herd.   By 2018, some regions the herd had rebounded from the state's worst outbreak of EHD in 2012.

The 2017 deer population was well below the state's carrying capacity, but populations were being managed with regard to social issues such as crop damage and deer-vehicle collisions.  The 2017 harvest data and reported estimate indicate a stable to slightly increasing population of about 660,000 deer, an increase in west-central counties. .About 677,000 deer in 2015, 645,000 in 2014, and 660,000 in 2013 estimated using harvest data. 

Deer herds were reported to be on the decline in 2015 largely as a result of high hunting pressure.  

After a 25 percent drop in the 2013 harvest, the number of deer licenses for 2014 were reduced by 4.1 percent to 592,457 and the state changed its objective to increasing deer populations.  Reduced again in 2015 to 577,244.  Reasons for the decline include adverse weather conditions, herd reduction efforts and deer mortality due to outbreaks of epizootic hemorrhagic disease (EHD). Deer management goals were generally maintaining to increasing the herd.   The 2014 harvest was 47 percent does, 49 percent in 2013.   A population estimate of 700,000 deer in 2013, down from an estimate in 2012 of 700,000 to 750,000 deer.  In 2011 the Northwest Herald reported on the "the widely-held opinion that there has been a drastic reduction in the population of whitetail deer in Illinois."

An estimate of 800,000 deer in 2009.   Dramatic harvest declines became a major issue. In 2008 the population was estimated at 800,000 to 1 million, the peak population was at around this time.   An estimate of nearly 800,000 deer in 2004.  The herd was under a managed decline from 2005.

About 750,000 deer in 1995, the peak during the 1990s. The Illinois General Assembly decided deer management should be linked to the number of auto-deer accidents. In 2008 the Task Force on Deer Population control recommended a 14 percent reduction in the rate of deer vehicle collisions from peak levels, the IDNR began increasing the harvest to achieve that goal in 2009. 

The 2017 deer population was well below the state's carrying capacity, but populations are being managed with regard to social issues such as crop damage and deer-vehicle collisions.  97 percent of the state's hunting property is privately owned with just 836,000 acres of public land.

Peak of the rut is November 8 - 11.

Chronic Wasting Disease (CWD) was first discovered in the deer herd in 2002 near Roscoe.  CWD was found in 19 northern counties by 2022 with over 150,000 deer tested. There were 1,383 for positives since testing began and 218 positives during Fiscal Year 2022.  A special CWD hunt was held in the 2022-23 season to reduced deer in infected areas to slow the spread.  Since 2002, 150,970 wild deer had been tested with 1,383 positive cases as of October, 2023.  

Epizootic Hemorrhagic Disease (EHD)  Some EHD mortality occurs every year, but is worst in drought conditions when deer congregate around muddy areas where the midges that spread the disease are found.  The worst recent outbreak was in 2012 when 2,043 dead deer reported to IDNR from 76 counties.  EHD nearly absent in 2014 and at low levels in 2015, 2016, and 2017.  Over 400 died in 2018.  A 2022 study documents the norhward expansion of the disease.  By October, 2023, 162,099 wild deer had been sampled statewide and 1,752 individual deer tested positive.

History:  Illinois forests were filled with deer as settlement began.  Over hunting during early settlement led to the virtual extinction of deer in Illinois by the late 1800's.  Deer hunting was limited in about half the state by 1873 with the last open season in 1900.  "  The last deer in Northern Illinois was reported in 1874, although there were still deer kept in pens across the state.  In 1901, Illinois imposed what was supposed to be a five-year moratorium on deer hunting. "As it turned out, whitetail deer basically had disappeared from the state, so that “temporary” closure lasted 56 years."  In the 1930s  By the 1930s, "the United States Forest Service and the Illinois Department of Conservation were releasing deer into the wilds of southern Illinois from game farms."  By 1940 the deer population was about 500.

Prior to the 1950s, occasional escapes and releases of deer from privately-owned preserves, translocations conducted by the Illinois Department of Conservation (currently IDNR) and the United States Forest Service, and possibly immigration of deer from adjacent states led to the reintroduction of white-tailed deer in Illinois." History  More History

"By 1950, white-tailed deer were known to inhabit 68 Illinois counties, and 33 counties were opened for deer hunting in 1957."  An estimate of 2,550 in 1949-1950 and more than 3,075 in 1950-1951 (p. 12). A census in 1957 showed about 15,000 deer concentrated in the far northwest of the state with some in the southern forests and the first modern firearm season opened.  

Even by the 1970's, it was rare to see a deer.  History   "... during the 1980s while (firearm) hunter success appeared to stabilize at 45-47 percent. During the 1980 firearm deer season, 20,700 deer were harvested by 75,800 permittees statewide compared to a peak harvest of 123,792 deer with 329,940 permits in 2005. Projections based upon population trend data indicate a stable to slightly declining statewide population from 2004 through 2008."   More history.

Deer Population Estimates:  1940:   500.    1950:  3,100.    1960:  19,195.    1968: 25,000.

Population Estimates from State Research:    1982:  299,493.   1988:  539,644.

Elk  Eliminated from Illinois by around 1830, at least one came back in 2023, killed by a car in Joliet.

Reindeer  A 17,000-year-old reindeer jaw old from Kendall County, IL reported discovered in 2021.

Mountain Lions  Eliminated from Illinois before the 1870s with occasional recent sightings typically of young lions from South Dakota.

Bobcat, once nearly extinct, the population grew to around 5,000 by 2014.

Coyotes, a 2019 study in the Chicago region fund coyotes accounted for 77.8& or mortality for deer fawns.

Report Poaching and Baiting:  1-877-2-DNR-LAW

Other useful links:

- Living with White-tailed Deer in Illinois, University of Illinois Extension   - Chronic Wasting Disease Statistics   - Deer Vehicle Accident Goals, used to set population targets.   - Fox Valley Wildlife Center  - Illinois Deer Hunting Information  

Below a graph of the Indiana Deer Hunt Results from 2011 to 2020 from IDNR