Data / Rankings / Population aged 18 to 64 / Counties in Illinois

Counties in Illinois by population aged 18 to 64

Champaign County had the highest population aged 18 to 64 of 102 counties in 2020, at 67.3%. Hardin County had the lowest, at 52.5%. The median was 57.5% and the figure for Illinois was 61.6%. Source: the U.S. Census Bureau.

Highest67.3Champaign County
Lowest52.5Hardin County
Median57.5102 counties
Illinois61.6History

Top 40 counties, 2020

Champaign County: 67.3 %Champaign County67.3Brown County: 66.7 %Brown County66.7McLean County: 63.9 %McLean County63.9Cook County: 63.8 %Cook County63.8Jackson County: 63.4 %Jackson County63.4DeKalb County: 63.3 %DeKalb County63.3Bond County: 63.1 %Bond County63.1Johnson County: 62.6 %Johnson County62.6McDonough County: 61.8 %McDonough County61.8Coles County: 61.6 %Coles County61.6Lawrence County: 61.6 %Lawrence County61.6Will County: 61.5 %Will County61.5McHenry County: 61.4 %McHenry County61.4Lake County: 61.2 %Lake County61.2DuPage County: 61 %DuPage County61Fayette County: 60.8 %Fayette County60.8Kendall County: 60.7 %Kendall County60.7Logan County: 60.5 %Logan County60.5Kane County: 60.4 %Kane County60.4Madison County: 60.4 %Madison County60.4Morgan County: 60.3 %Morgan County60.3Lee County: 60.1 %Lee County60.1Perry County: 60 %Perry County60Clinton County: 59.9 %Clinton County59.9Grundy County: 59.9 %Grundy County59.9St. Clair County: 59.7 %St. Clair County59.7Randolph County: 59.7 %Randolph County59.7Kankakee County: 59.4 %Kankakee County59.4Christian County: 59.4 %Christian County59.4LaSalle County: 59.2 %LaSalle County59.2Sangamon County: 59.2 %Sangamon County59.2Boone County: 59.1 %Boone County59.1Winnebago County: 58.9 %Winnebago County58.9Peoria County: 58.7 %Peoria County58.7Crawford County: 58.6 %Crawford County58.6De Witt County: 58.3 %De Witt County58.3Jersey County: 58.3 %Jersey County58.3Monroe County: 58.3 %Monroe County58.3Schuyler County: 58.2 %Schuyler County58.2Ogle County: 58.2 %Ogle County58.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2020 (%)Change on 2019
1Champaign County67.3-0.4 pts
2Brown County66.7-1 pts
3McLean County63.9-0.3 pts
4Cook County63.8-0.3 pts
5Jackson County63.4-0.7 pts
6DeKalb County63.3-0.4 pts
7Bond County63.1-0.1 pts
8Johnson County62.6-0.1 pts
9McDonough County61.8-0.5 pts
10Coles County61.6-0.4 pts
11Lawrence County61.6-0.4 pts
12Will County61.5-0.1 pts
13McHenry County61.4-0.3 pts
14Lake County61.2-0.2 pts
15DuPage County61-0.5 pts
16Fayette County60.8-0.4 pts
17Kendall County60.7+0.2 pts
18Logan County60.5-0.5 pts
19Kane County60.4-0.4 pts
20Madison County60.4-0.5 pts
21Morgan County60.3+0.7 pts
22Lee County60.1-0.6 pts
23Perry County60-0.6 pts
24Clinton County59.9-0.7 pts
25Grundy County59.9-0.2 pts
26St. Clair County59.7-0.6 pts
27Randolph County59.7-0.6 pts
28Kankakee County59.4-0.3 pts
29Christian County59.4-0.4 pts
30LaSalle County59.2-0.3 pts
31Sangamon County59.2-0.5 pts
32Boone County59.1+0.1 pts
33Winnebago County58.9-0.4 pts
34Peoria County58.7-0.6 pts
35Crawford County58.6-0.6 pts
36De Witt County58.3-0.4 pts
37Jersey County58.3-0.5 pts
38Monroe County58.3-0.8 pts
39Schuyler County58.2-0 pts
40Ogle County58.2-0.3 pts
41Williamson County58.2-0.3 pts
42Montgomery County58.1-0.8 pts
43Fulton County58.1-0.5 pts
44Cass County58-0.4 pts
45Putnam County58-0.3 pts
46Livingston County58-0.6 pts
47Rock Island County57.9-0.5 pts
48Carroll County57.8-0.2 pts
49Knox County57.7-0.7 pts
50Tazewell County57.5-0.3 pts
51Macoupin County57.5-0.5 pts
52Warren County57.5-0.6 pts
53Jefferson County57.4-0.4 pts
54Effingham County57.4-0.7 pts
55Washington County57.4-0.6 pts
56Macon County57.2-0.6 pts
57Menard County57.1-0.6 pts
58Adams County57-0.4 pts
59Union County56.8-0.8 pts
60Vermilion County56.7-0.6 pts
61Piatt County56.6-0.7 pts
62Franklin County56.5-0.5 pts
63Pulaski County56.5-0.2 pts
64Cumberland County56.4-0.5 pts
65Douglas County56.4-0.2 pts
66Bureau County56.4-0.4 pts
67Clark County56.4-0.7 pts
68Mason County56.4-0.2 pts
69Edgar County56.3-0.4 pts
70Woodford County56.3-0.2 pts
71Ford County56.2-0.6 pts
72Scott County56.2-2.1 pts
73Massac County56.2-0.1 pts
74Greene County56.1-0.4 pts
75Mercer County56.1-0.3 pts
76Wabash County56.1-1.2 pts
77Jasper County56-0.7 pts
78Whiteside County56-0.6 pts
79Henry County55.9-0.1 pts
80Alexander County55.9+0.5 pts
81Saline County55.8-0.6 pts
82Marion County55.8-0.8 pts
83Clay County55.7-0.5 pts
84Richland County55.7-0.6 pts
85Hamilton County55.7-0.3 pts
86Iroquois County55.5-0.5 pts
87Marshall County55.4-0.5 pts
88Shelby County55.4-0.7 pts
89Edwards County55.3-0.3 pts
90Pope County55.2+1.1 pts
91Stark County55.2-0 pts
92White County55.2-0.7 pts
93Gallatin County55.1+0.4 pts
94Stephenson County55-0.4 pts
95Wayne County55-0.3 pts
96Henderson County54.9-0.9 pts
97Hancock County54.7-0.8 pts
98Moultrie County54.6+0.1 pts
99Calhoun County54.40 pts
100Pike County54.2-1 pts
101Jo Daviess County52.8-0.5 pts
102Hardin County52.5-0.8 pts

Other periods

About this ranking

Residents aged 18 to 64 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.

Not comparable with working-age shares for ages 15 to 64 used in EU and World Bank statistics.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in Illinois by population aged 18 to 64, 2020) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Illinois by population aged 18 to 64, 2020. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2020. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in Illinois by population aged 18 to 64, 2020. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2020.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Illinois by population aged 18 to 64, 2020 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/illinois-counties?period=2020 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_illinois_by_2020,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Illinois by population aged 18 to 64, 2020}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2020. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Illinois by population aged 18 to 64, 2020
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/population-18-64/illinois-counties?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2020.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  -
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Questions

Which county has the highest population aged 18 to 64?

Champaign County, with 67.3% in 2020, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Hardin County, with 52.5% in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program, county population by age and sex: residents aged 18 to 64 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.

Population aged 18 to 64: other rankings

Counties in Illinois: more rankings