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

Counties in Illinois by population aged 18 to 64

Brown County had the highest population aged 18 to 64 of 102 counties in 2018, at 68.2%. Jo Daviess County had the lowest, at 53.5%. The median was 58.4% and the figure for Illinois was 62.2%. Source: the U.S. Census Bureau.

Highest68.2Brown County
Lowest53.5Jo Daviess County
Median58.4102 counties
Illinois62.2History

Top 40 counties, 2018

Brown County: 68.2 %Brown County68.2Champaign County: 68.2 %Champaign County68.2Jackson County: 64.9 %Jackson County64.9McLean County: 64.6 %McLean County64.6Cook County: 64.3 %Cook County64.3DeKalb County: 64.2 %DeKalb County64.2Bond County: 63.2 %Bond County63.2McDonough County: 63.1 %McDonough County63.1Coles County: 62.8 %Coles County62.8Lawrence County: 62.6 %Lawrence County62.6Johnson County: 62.5 %Johnson County62.5McHenry County: 62 %McHenry County62DuPage County: 61.9 %DuPage County61.9Will County: 61.8 %Will County61.8Lake County: 61.7 %Lake County61.7Logan County: 61.4 %Logan County61.4Perry County: 61.2 %Perry County61.2Madison County: 61.2 %Madison County61.2Clinton County: 61 %Clinton County61Lee County: 61 %Lee County61Fayette County: 61 %Fayette County61Kane County: 60.8 %Kane County60.8St. Clair County: 60.8 %St. Clair County60.8Randolph County: 60.8 %Randolph County60.8Kendall County: 60.6 %Kendall County60.6Grundy County: 60.3 %Grundy County60.3Christian County: 60 %Christian County60Kankakee County: 60 %Kankakee County60Sangamon County: 60 %Sangamon County60Morgan County: 60 %Morgan County60Winnebago County: 59.7 %Winnebago County59.7Crawford County: 59.7 %Crawford County59.7Monroe County: 59.7 %Monroe County59.7Peoria County: 59.7 %Peoria County59.7LaSalle County: 59.7 %LaSalle County59.7Montgomery County: 59.4 %Montgomery County59.4Jersey County: 59.2 %Jersey County59.2Schuyler County: 59.1 %Schuyler County59.1Boone County: 59.1 %Boone County59.1Fulton County: 59 %Fulton County59
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2018 (%)Change on 2017
1Brown County68.2-0.8 pts
2Champaign County68.2-0.5 pts
3Jackson County64.9-0.7 pts
4McLean County64.6-0.4 pts
5Cook County64.3-0.1 pts
6DeKalb County64.2-0.5 pts
7Bond County63.2-0.3 pts
8McDonough County63.1-1 pts
9Coles County62.8-0.7 pts
10Lawrence County62.6-0.1 pts
11Johnson County62.5+0.4 pts
12McHenry County62-0.2 pts
13DuPage County61.9-0.3 pts
14Will County61.8-0 pts
15Lake County61.7-0.2 pts
16Logan County61.4-0.5 pts
17Perry County61.2-0.4 pts
18Madison County61.2-0.3 pts
19Clinton County61-0.5 pts
20Lee County61-0.3 pts
21Fayette County61-0.2 pts
22Kane County60.8-0.1 pts
23St. Clair County60.8-0.4 pts
24Randolph County60.8-0.4 pts
25Kendall County60.6-0.1 pts
26Grundy County60.3-0.1 pts
27Christian County60-0.2 pts
28Kankakee County60-0.2 pts
29Sangamon County60-0.4 pts
30Morgan County60-0.5 pts
31Winnebago County59.7-0.2 pts
32Crawford County59.7-0.6 pts
33Monroe County59.7-0.4 pts
34Peoria County59.7-0.4 pts
35LaSalle County59.7-0.3 pts
36Montgomery County59.4-0.3 pts
37Jersey County59.2-0.3 pts
38Schuyler County59.1+0.1 pts
39Boone County59.1-0 pts
40Fulton County59-0.3 pts
41Williamson County58.9-0.3 pts
42De Witt County58.9-0.2 pts
43Knox County58.9-0.6 pts
44Rock Island County58.8-0.4 pts
45Ogle County58.8-0.2 pts
46Livingston County58.8-0.5 pts
47Effingham County58.7-0.5 pts
48Cass County58.7-0.2 pts
49Washington County58.5-0.4 pts
50Macoupin County58.5-0.5 pts
51Putnam County58.40 pts
52Jefferson County58.4-0.2 pts
53Warren County58.3-0.3 pts
54Macon County58.3-0.3 pts
55Tazewell County58.2-0.4 pts
56Carroll County58.1-0.2 pts
57Union County58-0.4 pts
58Menard County57.9-0.1 pts
59Scott County57.8-0.5 pts
60Cumberland County57.7-0.2 pts
61Adams County57.7-0.2 pts
62Wabash County57.6-0.7 pts
63Vermilion County57.6-0.3 pts
64Piatt County57.5-0.4 pts
65Jasper County57.5-0.4 pts
66Ford County57.3-0 pts
67Greene County57.3-1 pts
68Edgar County57.2-0.3 pts
69Mason County57.2-0.1 pts
70Franklin County57.2-0.2 pts
71Clark County57.2-0.3 pts
72Whiteside County57-0.3 pts
73Pulaski County57+0.3 pts
74Bureau County57-0.3 pts
75Saline County56.9-0.4 pts
76Woodford County56.9-0.5 pts
77Marion County56.8-0.5 pts
78Henderson County56.6-0 pts
79Douglas County56.5-0.3 pts
80Shelby County56.5-0.4 pts
81Marshall County56.5-0.4 pts
82Richland County56.4-0.6 pts
83Iroquois County56.4-0.2 pts
84Mercer County56.4-0.4 pts
85Henry County56.4-0.4 pts
86Clay County56.4-0.7 pts
87Massac County56.3-0.2 pts
88Edwards County56.2-0.6 pts
89White County56.1-0.1 pts
90Hamilton County56.1-0 pts
91Hancock County55.9-0.2 pts
92Pike County55.9-0.7 pts
93Stephenson County55.9-0.5 pts
94Alexander County55.7-0.2 pts
95Wayne County55.6-0.2 pts
96Stark County55.6-0.4 pts
97Gallatin County55.2-0.2 pts
98Pope County55.2-1 pts
99Moultrie County55-0.1 pts
100Calhoun County54.9-0.6 pts
101Hardin County54-0.6 pts
102Jo Daviess County53.5-0.5 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, 2018) [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, 2018. 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=2018. 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, 2018. 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=2018.

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, 2018 [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=2018 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_illinois_by_2018,
  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, 2018}},
  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=2018. 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, 2018
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=2018
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2018.
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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Rank Counties in Illinois by population aged 18 to 64 using official data, and cite the source.
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Questions

Which county has the highest population aged 18 to 64?

Brown County, with 68.2% in 2018, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Jo Daviess County, with 53.5% in 2018.

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