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 2024, at 66.5%. Hardin County had the lowest, at 50.1%. The median was 56% and the figure for Illinois was 60.8%. Source: the U.S. Census Bureau.

Highest66.5Champaign County
Lowest50.1Hardin County
Median56102 counties
Illinois60.8History

Top 40 counties, 2024

Champaign County: 66.5 %Champaign County66.5Brown County: 66.2 %Brown County66.2Cook County: 63.4 %Cook County63.4McLean County: 63.4 %McLean County63.4DeKalb County: 62.4 %DeKalb County62.4Jackson County: 62.1 %Jackson County62.1Johnson County: 62 %Johnson County62Bond County: 61.8 %Bond County61.8Kendall County: 61.5 %Kendall County61.5Will County: 61.1 %Will County61.1Lake County: 60.5 %Lake County60.5Kane County: 60.3 %Kane County60.3Coles County: 60.2 %Coles County60.2McHenry County: 60 %McHenry County60Grundy County: 59.9 %Grundy County59.9DuPage County: 59.7 %DuPage County59.7McDonough County: 59.7 %McDonough County59.7Perry County: 59.4 %Perry County59.4Logan County: 59.4 %Logan County59.4Madison County: 59.1 %Madison County59.1Fayette County: 59 %Fayette County59Boone County: 58.8 %Boone County58.8Lawrence County: 58.7 %Lawrence County58.7St. Clair County: 58.7 %St. Clair County58.7Morgan County: 58.5 %Morgan County58.5Christian County: 58.4 %Christian County58.4Crawford County: 58.2 %Crawford County58.2Lee County: 58.2 %Lee County58.2Randolph County: 58.2 %Randolph County58.2Kankakee County: 58.2 %Kankakee County58.2Sangamon County: 57.9 %Sangamon County57.9Clinton County: 57.9 %Clinton County57.9Winnebago County: 57.8 %Winnebago County57.8Fulton County: 57.6 %Fulton County57.6Williamson County: 57.6 %Williamson County57.6Cass County: 57.5 %Cass County57.5Peoria County: 57.4 %Peoria County57.4Montgomery County: 57.4 %Montgomery County57.4LaSalle County: 57.3 %LaSalle County57.3Tazewell County: 57.2 %Tazewell County57.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2024 (%)Change on 2023
1Champaign County66.5-0.3 pts
2Brown County66.2-0.4 pts
3Cook County63.4-0 pts
4McLean County63.4-0.1 pts
5DeKalb County62.4-0.1 pts
6Jackson County62.1-0 pts
7Johnson County62-0.5 pts
8Bond County61.8-0.2 pts
9Kendall County61.5+0.1 pts
10Will County61.1-0.1 pts
11Lake County60.5-0.1 pts
12Kane County60.30 pts
13Coles County60.2-0.4 pts
14McHenry County60-0.3 pts
15Grundy County59.9-0 pts
16DuPage County59.7-0.3 pts
17McDonough County59.7-1.2 pts
18Perry County59.4-0.4 pts
19Logan County59.4+0.2 pts
20Madison County59.1-0.3 pts
21Fayette County59-0.4 pts
22Boone County58.80 pts
23Lawrence County58.7+0.5 pts
24St. Clair County58.7-0.2 pts
25Morgan County58.5-0.5 pts
26Christian County58.4-0.3 pts
27Crawford County58.2-0.2 pts
28Lee County58.2-0.3 pts
29Randolph County58.2-0.2 pts
30Kankakee County58.2-0.2 pts
31Sangamon County57.9-0.3 pts
32Clinton County57.9-0.5 pts
33Winnebago County57.8-0.2 pts
34Fulton County57.6-0 pts
35Williamson County57.6-0 pts
36Cass County57.5-0.3 pts
37Peoria County57.4-0.2 pts
38Montgomery County57.4-0 pts
39LaSalle County57.3-0.4 pts
40Tazewell County57.2-0 pts
41Ogle County57.2-0.2 pts
42De Witt County56.9-0.1 pts
43Carroll County56.8-0.2 pts
44Jersey County56.7-0.3 pts
45Knox County56.6-0 pts
46Rock Island County56.5-0.3 pts
47Livingston County56.3-0.4 pts
48Monroe County56.3-0.5 pts
49Jefferson County56.2-0.4 pts
50Macoupin County56.1-0.2 pts
51Warren County56.1-0.3 pts
52Massac County56-0 pts
53Adams County55.9-0.3 pts
54Effingham County55.8-0.4 pts
55Mason County55.7-0.4 pts
56Washington County55.6-0.2 pts
57Richland County55.60 pts
58Franklin County55.6-0.5 pts
59Vermilion County55.6-0.3 pts
60Menard County55.6-0.4 pts
61Union County55.5-0.4 pts
62Mercer County55.5-0.3 pts
63Macon County55.5-0.3 pts
64Putnam County55.5-0.5 pts
65Bureau County55.5-0.4 pts
66Clark County55.4-0.1 pts
67Douglas County55.3-0.3 pts
68Saline County55.3-0.3 pts
69Greene County55.2-0 pts
70Schuyler County55.1-0.8 pts
71Ford County55.1-0.1 pts
72Woodford County55-0.4 pts
73Pulaski County54.9-0.4 pts
74Wabash County54.9-0 pts
75Henry County54.9-0.1 pts
76Whiteside County54.8-0.2 pts
77Edwards County54.8-0.5 pts
78Gallatin County54.7+0.3 pts
79Piatt County54.6-0.7 pts
80Hamilton County54.60 pts
80White County54.60 pts
82Marion County54.6-0.2 pts
83Cumberland County54.6-0.6 pts
84Scott County54.5-0.9 pts
85Wayne County54.5-0.2 pts
86Stark County54.5-0.2 pts
87Iroquois County54.4-0.3 pts
88Edgar County54.4-0.3 pts
89Clay County54.4-0.3 pts
90Marshall County54-0.6 pts
91Jasper County53.8-0.5 pts
92Pope County53.8+0.3 pts
93Shelby County53.8-0.3 pts
94Stephenson County53.7-0.2 pts
95Pike County53.7+0.1 pts
96Moultrie County53.7-0.1 pts
97Alexander County53.3-0.3 pts
98Calhoun County53.30 pts
99Hancock County52.7-0.4 pts
100Henderson County52-0.9 pts
101Jo Daviess County51.1-0.7 pts
102Hardin County50.1-0.7 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, 2024) [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, 2024. 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=2024. 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, 2024. 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=2024.

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, 2024 [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=2024 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_illinois_by_2024,
  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, 2024}},
  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=2024. 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, 2024
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=2024
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2024.
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 66.5% in 2024, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Hardin County, with 50.1% in 2024.

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