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 2015, at 70.1%. Hardin County had the lowest, at 55.2%. The median was 59.5% and the figure for Illinois was 62.8%. Source: the U.S. Census Bureau.

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Highest70.1Brown County
Lowest55.2Hardin County
Median59.5102 counties
Illinois62.8History

Map of counties, 2015

Adams County: 58.5 %Alexander County: 56.8 %Bond County: 64.1 %Boone County: 59.4 %Brown County: 70.1 %Bureau County: 57.9 %Calhoun County: 56 %Carroll County: 58.4 %Cass County: 59.7 %Champaign County: 69.6 %Christian County: 60.2 %Clark County: 58.2 %Clay County: 57.9 %Clinton County: 62.1 %Coles County: 65.1 %Cook County: 64.6 %Crawford County: 60.8 %Cumberland County: 58.9 %DeKalb County: 65.6 %De Witt County: 59.6 %Douglas County: 57.2 %DuPage County: 62.9 %Edgar County: 58.2 %Edwards County: 57.5 %Effingham County: 59.5 %Fayette County: 61.7 %Ford County: 57.5 %Franklin County: 58.1 %Fulton County: 60.2 %Gallatin County: 56.6 %Greene County: 58.8 %Grundy County: 60.9 %Hamilton County: 57.1 %Hancock County: 56.5 %Hardin County: 55.2 %Henderson County: 56.9 %Henry County: 57.7 %Iroquois County: 57.2 %Jackson County: 67.7 %Jasper County: 58.6 %Jefferson County: 60 %Jersey County: 60.4 %Jo Daviess County: 55.6 %Johnson County: 63.3 %Kane County: 61.1 %Kankakee County: 60.8 %Kendall County: 60.8 %Knox County: 60.4 %Lake County: 62.2 %LaSalle County: 60.5 %Lawrence County: 63.4 %Lee County: 61.9 %Livingston County: 60.2 %Logan County: 62.8 %McDonough County: 66.1 %McHenry County: 62.6 %McLean County: 65.9 %Macon County: 59.5 %Macoupin County: 59.4 %Madison County: 62 %Marion County: 58 %Marshall County: 57.9 %Mason County: 57.6 %Massac County: 57.3 %Menard County: 59.3 %Mercer County: 57.2 %Monroe County: 60.7 %Montgomery County: 60.5 %Morgan County: 60.9 %Moultrie County: 56.2 %Ogle County: 59.5 %Peoria County: 60.9 %Perry County: 62.4 %Piatt County: 58.7 %Pike County: 56.9 %Pope County: 57.6 %Pulaski County: 58 %Putnam County: 59.6 %Randolph County: 62.5 %Richland County: 57.7 %Rock Island County: 59.9 %St. Clair County: 61.9 %Saline County: 57.9 %Sangamon County: 61.2 %Schuyler County: 59.5 %Scott County: 58.8 %Shelby County: 57.7 %Stark County: 56.3 %Stephenson County: 57.3 %Tazewell County: 59.4 %Union County: 59.1 %Vermilion County: 58.5 %Wabash County: 58.8 %Warren County: 59.5 %Washington County: 60.3 %Wayne County: 56.7 %White County: 56.3 %Whiteside County: 57.9 %Will County: 61.9 %Williamson County: 59.8 %Winnebago County: 60.5 %Woodford County: 58.3 %
  • Under 57
  • 57 to 58
  • 58 to 59
  • 59 to 60
  • 60 to 62
  • 62 and over
%, 2015. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2015

Brown County: 70.1 %Brown County70.1Champaign County: 69.6 %Champaign County69.6Jackson County: 67.7 %Jackson County67.7McDonough County: 66.1 %McDonough County66.1McLean County: 65.9 %McLean County65.9DeKalb County: 65.6 %DeKalb County65.6Coles County: 65.1 %Coles County65.1Cook County: 64.6 %Cook County64.6Bond County: 64.1 %Bond County64.1Lawrence County: 63.4 %Lawrence County63.4Johnson County: 63.3 %Johnson County63.3DuPage County: 62.9 %DuPage County62.9Logan County: 62.8 %Logan County62.8McHenry County: 62.6 %McHenry County62.6Randolph County: 62.5 %Randolph County62.5Perry County: 62.4 %Perry County62.4Lake County: 62.2 %Lake County62.2Clinton County: 62.1 %Clinton County62.1Madison County: 62 %Madison County62Will County: 61.9 %Will County61.9Lee County: 61.9 %Lee County61.9St. Clair County: 61.9 %St. Clair County61.9Fayette County: 61.7 %Fayette County61.7Sangamon County: 61.2 %Sangamon County61.2Kane County: 61.1 %Kane County61.1Grundy County: 60.9 %Grundy County60.9Morgan County: 60.9 %Morgan County60.9Peoria County: 60.9 %Peoria County60.9Kankakee County: 60.8 %Kankakee County60.8Crawford County: 60.8 %Crawford County60.8Kendall County: 60.8 %Kendall County60.8Monroe County: 60.7 %Monroe County60.7Winnebago County: 60.5 %Winnebago County60.5LaSalle County: 60.5 %LaSalle County60.5Montgomery County: 60.5 %Montgomery County60.5Knox County: 60.4 %Knox County60.4Jersey County: 60.4 %Jersey County60.4Washington County: 60.3 %Washington County60.3Christian County: 60.2 %Christian County60.2Fulton County: 60.2 %Fulton County60.2Brown County: 70.1 %Brown County70.1Champaign County: 69.6 %Champaign County69.6Jackson County: 67.7 %Jackson County67.7McDonough County: 66.1 %McDonough County66.1McLean County: 65.9 %McLean County65.9DeKalb County: 65.6 %DeKalb County65.6Coles County: 65.1 %Coles County65.1Cook County: 64.6 %Cook County64.6Bond County: 64.1 %Bond County64.1Lawrence County: 63.4 %Lawrence County63.4Johnson County: 63.3 %Johnson County63.3DuPage County: 62.9 %DuPage County62.9Logan County: 62.8 %Logan County62.8McHenry County: 62.6 %McHenry County62.6Randolph County: 62.5 %Randolph County62.5Perry County: 62.4 %Perry County62.4Lake County: 62.2 %Lake County62.2Clinton County: 62.1 %Clinton County62.1Madison County: 62 %Madison County62Will County: 61.9 %Will County61.9Lee County: 61.9 %Lee County61.9St. Clair County: 61.9 %St. Clair County61.9Fayette County: 61.7 %Fayette County61.7Sangamon County: 61.2 %Sangamon County61.2Kane County: 61.1 %Kane County61.1Grundy County: 60.9 %Grundy County60.9Morgan County: 60.9 %Morgan County60.9Peoria County: 60.9 %Peoria County60.9Kankakee County: 60.8 %Kankakee County60.8Crawford County: 60.8 %Crawford County60.8Kendall County: 60.8 %Kendall County60.8Monroe County: 60.7 %Monroe County60.7Winnebago County: 60.5 %Winnebago County60.5LaSalle County: 60.5 %LaSalle County60.5Montgomery County: 60.5 %Montgomery County60.5Knox County: 60.4 %Knox County60.4Jersey County: 60.4 %Jersey County60.4Washington County: 60.3 %Washington County60.3Christian County: 60.2 %Christian County60.2Fulton County: 60.2 %Fulton County60.2
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2015 (%)Change on 2014
1Brown County70.1-0.6 pts
2Champaign County69.6-0.2 pts
3Jackson County67.7-0.6 pts
4McDonough County66.1-0.9 pts
5McLean County65.9-0.4 pts
6DeKalb County65.6-0.5 pts
7Coles County65.1-0.6 pts
8Cook County64.6-0.1 pts
9Bond County64.1-0.1 pts
10Lawrence County63.4-0.4 pts
11Johnson County63.3-0.7 pts
12DuPage County62.9-0.2 pts
13Logan County62.8-0.5 pts
14McHenry County62.6-0.1 pts
15Randolph County62.5-0.3 pts
16Perry County62.4-0.4 pts
17Lake County62.20 pts
18Clinton County62.1-0.4 pts
19Madison County62-0.2 pts
20Will County61.9-0.1 pts
21Lee County61.9-0.4 pts
21St. Clair County61.9-0.1 pts
23Fayette County61.70 pts
24Sangamon County61.2-0.4 pts
25Kane County61.1-0 pts
26Grundy County60.9-0.2 pts
27Morgan County60.9-0.6 pts
28Peoria County60.9-0.3 pts
29Kankakee County60.8-0.1 pts
30Crawford County60.8-0.7 pts
31Kendall County60.8-0 pts
32Monroe County60.7-0.4 pts
33Winnebago County60.5-0.2 pts
34LaSalle County60.5-0.2 pts
35Montgomery County60.5-0.5 pts
36Knox County60.4-0.2 pts
37Jersey County60.40 pts
38Washington County60.3-0.3 pts
39Christian County60.2-0.1 pts
40Fulton County60.2-0.3 pts
41Livingston County60.2-0.6 pts
42Jefferson County60-0.6 pts
43Rock Island County59.9-0.3 pts
44Williamson County59.8-0.6 pts
45Cass County59.70 pts
46Putnam County59.6-0.8 pts
47De Witt County59.6-0.5 pts
48Effingham County59.5-0.3 pts
49Schuyler County59.5-0.5 pts
50Ogle County59.5-0.1 pts
51Warren County59.5-0.2 pts
52Macon County59.5-0.4 pts
53Macoupin County59.4-0.2 pts
54Boone County59.4-0.2 pts
55Tazewell County59.4-0.3 pts
56Menard County59.3-0.1 pts
57Union County59.1-0.4 pts
58Cumberland County58.9-0.2 pts
59Scott County58.8-0.6 pts
60Greene County58.8-0.1 pts
61Wabash County58.8-0.4 pts
62Piatt County58.7-0.5 pts
63Jasper County58.6-0.1 pts
64Vermilion County58.5-0.2 pts
65Adams County58.5-0.3 pts
66Carroll County58.4-0.1 pts
67Woodford County58.3-0.3 pts
68Clark County58.2-0.4 pts
69Edgar County58.2-0 pts
70Franklin County58.1-0.2 pts
71Pulaski County58-0.4 pts
72Marion County58-0.4 pts
73Saline County57.9-0.5 pts
74Whiteside County57.9-0.4 pts
75Marshall County57.9-0.2 pts
76Bureau County57.9-0.4 pts
77Clay County57.9-0.2 pts
78Henry County57.7-0.3 pts
79Richland County57.7-0.2 pts
80Shelby County57.7-0.2 pts
81Mason County57.6-0.4 pts
82Pope County57.6-1.2 pts
83Edwards County57.5-0.2 pts
84Ford County57.5-0.1 pts
85Massac County57.3-0.5 pts
86Stephenson County57.3-0.5 pts
87Mercer County57.2-0.3 pts
88Iroquois County57.2-0.1 pts
89Douglas County57.2-0.4 pts
90Hamilton County57.1-0.1 pts
91Pike County56.9-1 pts
92Henderson County56.9-0.3 pts
93Alexander County56.8-0.1 pts
94Wayne County56.7-0.5 pts
95Gallatin County56.6-0.4 pts
96Hancock County56.5-0.6 pts
97White County56.3-0.1 pts
98Stark County56.3-0.5 pts
99Moultrie County56.2-0.3 pts
100Calhoun County56-0.5 pts
101Jo Daviess County55.6-0.6 pts
102Hardin County55.2-0.1 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, 2015) [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, 2015. 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=2015. 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, 2015. 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=2015.

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, 2015 [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=2015 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_illinois_by_2015,
  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, 2015}},
  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=2015. 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, 2015
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=2015
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/illinois-counties?period=2015.
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?

Brown County, with 70.1% in 2015, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Hardin County, with 55.2% in 2015.

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