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

Counties in Iowa by population aged 18 to 64

Story County had the highest population aged 18 to 64 of 99 counties in 2021, at 70%. Davis County had the lowest, at 51.6%. The median was 55.1% and the figure for Iowa was 58.6%. Source: the U.S. Census Bureau.

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Highest70Story County
Lowest51.6Davis County
Median55.199 counties
Iowa58.6History

Map of counties, 2021

Adair County: 54.3 %Adams County: 54.7 %Allamakee County: 53.1 %Appanoose County: 54.3 %Audubon County: 53.2 %Benton County: 57.5 %Black Hawk County: 59.9 %Boone County: 57 %Bremer County: 56.5 %Buchanan County: 54.6 %Buena Vista County: 57.3 %Butler County: 52.7 %Calhoun County: 55.1 %Carroll County: 53.9 %Cass County: 53.6 %Cedar County: 56.4 %Cerro Gordo County: 55.8 %Cherokee County: 52.6 %Chickasaw County: 54.2 %Clarke County: 55 %Clay County: 54.5 %Clayton County: 53.3 %Clinton County: 56.5 %Crawford County: 54.9 %Dallas County: 60.1 %Davis County: 51.6 %Decatur County: 56.7 %Delaware County: 55.4 %Des Moines County: 56.2 %Dickinson County: 52.7 %Dubuque County: 58.2 %Emmet County: 54.8 %Fayette County: 55.4 %Floyd County: 54 %Franklin County: 54 %Fremont County: 54.2 %Greene County: 53.6 %Grundy County: 54.3 %Guthrie County: 54.4 %Hamilton County: 55.3 %Hancock County: 53.3 %Hardin County: 54.4 %Harrison County: 55.7 %Henry County: 59 %Howard County: 53.8 %Humboldt County: 54.3 %Ida County: 53.3 %Iowa County: 56.7 %Jackson County: 55.6 %Jasper County: 58.2 %Jefferson County: 53 %Johnson County: 66.9 %Jones County: 57.6 %Keokuk County: 54.2 %Kossuth County: 53.3 %Lee County: 55.3 %Linn County: 60 %Louisa County: 57.4 %Lucas County: 54.1 %Lyon County: 52.8 %Madison County: 56.1 %Mahaska County: 56.5 %Marion County: 56.6 %Marshall County: 55.4 %Mills County: 56.1 %Mitchell County: 52.7 %Monona County: 52.9 %Monroe County: 55.2 %Montgomery County: 54.4 %Muscatine County: 57.7 %O'Brien County: 54.4 %Osceola County: 55.6 %Page County: 55.9 %Palo Alto County: 53.4 %Plymouth County: 55.4 %Pocahontas County: 53.3 %Polk County: 61.2 %Pottawattamie County: 58.2 %Poweshiek County: 58.6 %Ringgold County: 52.1 %Sac County: 53.2 %Scott County: 59.1 %Shelby County: 54 %Sioux County: 56.3 %Story County: 70 %Tama County: 54.9 %Taylor County: 52.2 %Union County: 56.1 %Van Buren County: 52.4 %Wapello County: 57.1 %Warren County: 57.5 %Washington County: 54.6 %Wayne County: 51.9 %Webster County: 59.1 %Winnebago County: 56.4 %Winneshiek County: 58.3 %Woodbury County: 58.4 %Worth County: 55.1 %Wright County: 52.9 %
  • Under 53
  • 53 to 54
  • 54 to 55
  • 55 to 56
  • 56 to 58
  • 58 and over
%, 2021. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2021

Story County: 70 %Story County70Johnson County: 66.9 %Johnson County66.9Polk County: 61.2 %Polk County61.2Dallas County: 60.1 %Dallas County60.1Linn County: 60 %Linn County60Black Hawk County: 59.9 %Black Hawk County59.9Webster County: 59.1 %Webster County59.1Scott County: 59.1 %Scott County59.1Henry County: 59 %Henry County59Poweshiek County: 58.6 %Poweshiek County58.6Woodbury County: 58.4 %Woodbury County58.4Winneshiek County: 58.3 %Winneshiek County58.3Jasper County: 58.2 %Jasper County58.2Pottawattamie County: 58.2 %Pottawattamie County58.2Dubuque County: 58.2 %Dubuque County58.2Muscatine County: 57.7 %Muscatine County57.7Jones County: 57.6 %Jones County57.6Benton County: 57.5 %Benton County57.5Warren County: 57.5 %Warren County57.5Louisa County: 57.4 %Louisa County57.4Buena Vista County: 57.3 %Buena Vista County57.3Wapello County: 57.1 %Wapello County57.1Boone County: 57 %Boone County57Iowa County: 56.7 %Iowa County56.7Decatur County: 56.7 %Decatur County56.7Marion County: 56.6 %Marion County56.6Clinton County: 56.5 %Clinton County56.5Bremer County: 56.5 %Bremer County56.5Mahaska County: 56.5 %Mahaska County56.5Cedar County: 56.4 %Cedar County56.4Winnebago County: 56.4 %Winnebago County56.4Sioux County: 56.3 %Sioux County56.3Des Moines County: 56.2 %Des Moines County56.2Mills County: 56.1 %Mills County56.1Madison County: 56.1 %Madison County56.1Union County: 56.1 %Union County56.1Page County: 55.9 %Page County55.9Cerro Gordo County: 55.8 %Cerro Gordo County55.8Harrison County: 55.7 %Harrison County55.7Osceola County: 55.6 %Osceola County55.6Story County: 70 %Story County70Johnson County: 66.9 %Johnson County66.9Polk County: 61.2 %Polk County61.2Dallas County: 60.1 %Dallas County60.1Linn County: 60 %Linn County60Black Hawk County: 59.9 %Black Hawk County59.9Webster County: 59.1 %Webster County59.1Scott County: 59.1 %Scott County59.1Henry County: 59 %Henry County59Poweshiek County: 58.6 %Poweshiek County58.6Woodbury County: 58.4 %Woodbury County58.4Winneshiek County: 58.3 %Winneshiek County58.3Jasper County: 58.2 %Jasper County58.2Pottawattamie County: 58.2 %Pottawattamie County58.2Dubuque County: 58.2 %Dubuque County58.2Muscatine County: 57.7 %Muscatine County57.7Jones County: 57.6 %Jones County57.6Benton County: 57.5 %Benton County57.5Warren County: 57.5 %Warren County57.5Louisa County: 57.4 %Louisa County57.4Buena Vista County: 57.3 %Buena Vista County57.3Wapello County: 57.1 %Wapello County57.1Boone County: 57 %Boone County57Iowa County: 56.7 %Iowa County56.7Decatur County: 56.7 %Decatur County56.7Marion County: 56.6 %Marion County56.6Clinton County: 56.5 %Clinton County56.5Bremer County: 56.5 %Bremer County56.5Mahaska County: 56.5 %Mahaska County56.5Cedar County: 56.4 %Cedar County56.4Winnebago County: 56.4 %Winnebago County56.4Sioux County: 56.3 %Sioux County56.3Des Moines County: 56.2 %Des Moines County56.2Mills County: 56.1 %Mills County56.1Madison County: 56.1 %Madison County56.1Union County: 56.1 %Union County56.1Page County: 55.9 %Page County55.9Cerro Gordo County: 55.8 %Cerro Gordo County55.8Harrison County: 55.7 %Harrison County55.7Osceola County: 55.6 %Osceola County55.6
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)Change on 2020
1Story County70-0.1 pts
2Johnson County66.9-0.1 pts
3Polk County61.2+0.1 pts
4Dallas County60.1+0.1 pts
5Linn County60-0.2 pts
6Black Hawk County59.9-0.4 pts
7Webster County59.1+0.2 pts
8Scott County59.1-0.2 pts
9Henry County59-0.1 pts
10Poweshiek County58.6-0.3 pts
11Woodbury County58.4-0.1 pts
12Winneshiek County58.3-0.6 pts
13Jasper County58.2-0.1 pts
14Pottawattamie County58.2-0.2 pts
15Dubuque County58.2-0.2 pts
16Muscatine County57.7-0.1 pts
17Jones County57.6-0.1 pts
18Benton County57.5-0.2 pts
19Warren County57.5-0.1 pts
20Louisa County57.4+0.1 pts
21Buena Vista County57.3-0 pts
22Wapello County57.1-0.2 pts
23Boone County57+0.1 pts
24Iowa County56.7-0.1 pts
25Decatur County56.7+0.2 pts
26Marion County56.6-0.4 pts
27Clinton County56.5-0.3 pts
28Bremer County56.5+0.2 pts
29Mahaska County56.5-0.2 pts
30Cedar County56.4-0.3 pts
31Winnebago County56.4-0.6 pts
32Sioux County56.3-0.2 pts
33Des Moines County56.2-0.1 pts
34Mills County56.1-0.2 pts
35Madison County56.1-0.3 pts
36Union County56.1+0.1 pts
37Page County55.9-0 pts
38Cerro Gordo County55.8-0.5 pts
39Harrison County55.7-0.3 pts
40Osceola County55.6-0.5 pts
41Jackson County55.6-0.5 pts
42Plymouth County55.4-0.3 pts
43Fayette County55.4-0.2 pts
44Delaware County55.4-0.5 pts
45Marshall County55.4-0.1 pts
46Lee County55.3-0.4 pts
47Hamilton County55.3-0.4 pts
48Monroe County55.2+0.3 pts
49Calhoun County55.1-0.4 pts
50Worth County55.1-0.5 pts
51Clarke County55-0.3 pts
52Tama County54.9+0.1 pts
53Crawford County54.9-0.3 pts
54Emmet County54.8-0.1 pts
55Adams County54.7-0.6 pts
56Washington County54.6-0.3 pts
57Buchanan County54.6-0.3 pts
58Clay County54.5-0.8 pts
59O'Brien County54.4-0.2 pts
60Guthrie County54.4+0.4 pts
60Hardin County54.4-0.1 pts
62Montgomery County54.4-0.4 pts
63Grundy County54.3-0.3 pts
64Adair County54.3+0.1 pts
65Appanoose County54.3+0.1 pts
66Humboldt County54.3-0.4 pts
67Keokuk County54.2-0.1 pts
68Chickasaw County54.2-0.4 pts
69Fremont County54.2+0.1 pts
70Lucas County54.1-0.5 pts
71Franklin County54-0.4 pts
72Floyd County54-0.1 pts
73Shelby County54-0.4 pts
74Carroll County53.9-0.4 pts
75Howard County53.8-0 pts
76Cass County53.6-0.3 pts
77Greene County53.6-0.2 pts
78Palo Alto County53.4-0.6 pts
79Clayton County53.3-0.6 pts
80Kossuth County53.3-0.6 pts
81Pocahontas County53.3-0.2 pts
82Ida County53.3-0.5 pts
83Hancock County53.3-0.4 pts
84Audubon County53.2-0.2 pts
85Sac County53.2+0.1 pts
86Allamakee County53.1-0.4 pts
87Jefferson County53-0.6 pts
88Wright County52.9-0.5 pts
89Monona County52.9+0.1 pts
90Lyon County52.80 pts
91Dickinson County52.7-0.5 pts
92Mitchell County52.7-0.5 pts
93Butler County52.7-0.5 pts
94Cherokee County52.6-0.8 pts
95Van Buren County52.4-0.5 pts
96Taylor County52.2-0.3 pts
97Ringgold County52.1+0.5 pts
98Wayne County51.9-0.4 pts
99Davis County51.6-0.5 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 Iowa by population aged 18 to 64, 2021) [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 Iowa by population aged 18 to 64, 2021. 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/iowa-counties?period=2021. 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 Iowa by population aged 18 to 64, 2021. 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/iowa-counties?period=2021.

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 Iowa by population aged 18 to 64, 2021 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-18-64/iowa-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_iowa_by_2021,
  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 Iowa by population aged 18 to 64, 2021}},
  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/iowa-counties?period=2021. 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 Iowa by population aged 18 to 64, 2021
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/iowa-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/iowa-counties?period=2021.
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?

Story County, with 70% in 2021, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Davis County, with 51.6% in 2021.

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 Iowa: more rankings