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 2019, at 70.3%. Ringgold County had the lowest, at 51.7%. The median was 55.7% and the figure for Iowa was 59.1%. Source: the U.S. Census Bureau.

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Highest70.3Story County
Lowest51.7Ringgold County
Median55.799 counties
Iowa59.1History

Map of counties, 2019

Adair County: 54.9 %Adams County: 54.9 %Allamakee County: 53.8 %Appanoose County: 54.6 %Audubon County: 54 %Benton County: 58 %Black Hawk County: 60.7 %Boone County: 57.2 %Bremer County: 56.7 %Buchanan County: 55.4 %Buena Vista County: 57.8 %Butler County: 53.8 %Calhoun County: 56.1 %Carroll County: 55 %Cass County: 54.5 %Cedar County: 56.9 %Cerro Gordo County: 56.9 %Cherokee County: 53.8 %Chickasaw County: 55.2 %Clarke County: 55.4 %Clay County: 55.7 %Clayton County: 54.6 %Clinton County: 57.3 %Crawford County: 55.5 %Dallas County: 59.9 %Davis County: 52.8 %Decatur County: 56.1 %Delaware County: 56.4 %Des Moines County: 56.8 %Dickinson County: 53.9 %Dubuque County: 58.8 %Emmet County: 55.3 %Fayette County: 56.4 %Floyd County: 54.9 %Franklin County: 54.6 %Fremont County: 54.5 %Greene County: 54.5 %Grundy County: 55.1 %Guthrie County: 53.9 %Hamilton County: 56.2 %Hancock County: 54.1 %Hardin County: 54.7 %Harrison County: 56.4 %Henry County: 59.4 %Howard County: 53.9 %Humboldt County: 54.9 %Ida County: 53.3 %Iowa County: 57.3 %Jackson County: 56.8 %Jasper County: 58.6 %Jefferson County: 55.1 %Johnson County: 67.4 %Jones County: 58.3 %Keokuk County: 55.2 %Kossuth County: 54.3 %Lee County: 56.4 %Linn County: 60.4 %Louisa County: 57.7 %Lucas County: 54.9 %Lyon County: 53.2 %Madison County: 56.7 %Mahaska County: 57.2 %Marion County: 57.2 %Marshall County: 55.7 %Mills County: 56.7 %Mitchell County: 53.4 %Monona County: 52.9 %Monroe County: 55.4 %Montgomery County: 55.4 %Muscatine County: 58.2 %O'Brien County: 55.1 %Osceola County: 56.3 %Page County: 56.4 %Palo Alto County: 54.3 %Plymouth County: 56 %Pocahontas County: 54.1 %Polk County: 61.6 %Pottawattamie County: 58.9 %Poweshiek County: 59.1 %Ringgold County: 51.7 %Sac County: 53.5 %Scott County: 59.7 %Shelby County: 54.5 %Sioux County: 56.6 %Story County: 70.3 %Tama County: 55.6 %Taylor County: 53 %Union County: 56.4 %Van Buren County: 53.9 %Wapello County: 57.9 %Warren County: 57.9 %Washington County: 55.2 %Wayne County: 53.6 %Webster County: 59.4 %Winnebago County: 57.5 %Winneshiek County: 59.5 %Woodbury County: 58.9 %Worth County: 56.6 %Wright County: 53.7 %
  • Under 54
  • 54 to 55
  • 55 to 56
  • 56 to 57
  • 57 to 58
  • 58 and over
%, 2019. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2019

Story County: 70.3 %Story County70.3Johnson County: 67.4 %Johnson County67.4Polk County: 61.6 %Polk County61.6Black Hawk County: 60.7 %Black Hawk County60.7Linn County: 60.4 %Linn County60.4Dallas County: 59.9 %Dallas County59.9Scott County: 59.7 %Scott County59.7Winneshiek County: 59.5 %Winneshiek County59.5Webster County: 59.4 %Webster County59.4Henry County: 59.4 %Henry County59.4Poweshiek County: 59.1 %Poweshiek County59.1Pottawattamie County: 58.9 %Pottawattamie County58.9Woodbury County: 58.9 %Woodbury County58.9Dubuque County: 58.8 %Dubuque County58.8Jasper County: 58.6 %Jasper County58.6Jones County: 58.3 %Jones County58.3Muscatine County: 58.2 %Muscatine County58.2Benton County: 58 %Benton County58Warren County: 57.9 %Warren County57.9Wapello County: 57.9 %Wapello County57.9Buena Vista County: 57.8 %Buena Vista County57.8Louisa County: 57.7 %Louisa County57.7Winnebago County: 57.5 %Winnebago County57.5Iowa County: 57.3 %Iowa County57.3Clinton County: 57.3 %Clinton County57.3Marion County: 57.2 %Marion County57.2Boone County: 57.2 %Boone County57.2Mahaska County: 57.2 %Mahaska County57.2Cerro Gordo County: 56.9 %Cerro Gordo County56.9Cedar County: 56.9 %Cedar County56.9Jackson County: 56.8 %Jackson County56.8Des Moines County: 56.8 %Des Moines County56.8Bremer County: 56.7 %Bremer County56.7Madison County: 56.7 %Madison County56.7Mills County: 56.7 %Mills County56.7Sioux County: 56.6 %Sioux County56.6Worth County: 56.6 %Worth County56.6Union County: 56.4 %Union County56.4Delaware County: 56.4 %Delaware County56.4Lee County: 56.4 %Lee County56.4Story County: 70.3 %Story County70.3Johnson County: 67.4 %Johnson County67.4Polk County: 61.6 %Polk County61.6Black Hawk County: 60.7 %Black Hawk County60.7Linn County: 60.4 %Linn County60.4Dallas County: 59.9 %Dallas County59.9Scott County: 59.7 %Scott County59.7Winneshiek County: 59.5 %Winneshiek County59.5Webster County: 59.4 %Webster County59.4Henry County: 59.4 %Henry County59.4Poweshiek County: 59.1 %Poweshiek County59.1Pottawattamie County: 58.9 %Pottawattamie County58.9Woodbury County: 58.9 %Woodbury County58.9Dubuque County: 58.8 %Dubuque County58.8Jasper County: 58.6 %Jasper County58.6Jones County: 58.3 %Jones County58.3Muscatine County: 58.2 %Muscatine County58.2Benton County: 58 %Benton County58Warren County: 57.9 %Warren County57.9Wapello County: 57.9 %Wapello County57.9Buena Vista County: 57.8 %Buena Vista County57.8Louisa County: 57.7 %Louisa County57.7Winnebago County: 57.5 %Winnebago County57.5Iowa County: 57.3 %Iowa County57.3Clinton County: 57.3 %Clinton County57.3Marion County: 57.2 %Marion County57.2Boone County: 57.2 %Boone County57.2Mahaska County: 57.2 %Mahaska County57.2Cerro Gordo County: 56.9 %Cerro Gordo County56.9Cedar County: 56.9 %Cedar County56.9Jackson County: 56.8 %Jackson County56.8Des Moines County: 56.8 %Des Moines County56.8Bremer County: 56.7 %Bremer County56.7Madison County: 56.7 %Madison County56.7Mills County: 56.7 %Mills County56.7Sioux County: 56.6 %Sioux County56.6Worth County: 56.6 %Worth County56.6Union County: 56.4 %Union County56.4Delaware County: 56.4 %Delaware County56.4Lee County: 56.4 %Lee County56.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2019 (%)Change on 2018
1Story County70.3-0.3 pts
2Johnson County67.4-0.4 pts
3Polk County61.6-0.2 pts
4Black Hawk County60.7-0.6 pts
5Linn County60.4-0.2 pts
6Dallas County59.9+0.1 pts
7Scott County59.7-0.4 pts
8Winneshiek County59.5-0.7 pts
9Webster County59.4-0.4 pts
10Henry County59.4-0.4 pts
11Poweshiek County59.1-0.1 pts
12Pottawattamie County58.9-0.2 pts
13Woodbury County58.9-0 pts
14Dubuque County58.8-0.5 pts
15Jasper County58.6+0.1 pts
16Jones County58.3-0 pts
17Muscatine County58.2-0.3 pts
18Benton County58-0.3 pts
19Warren County57.9-0.4 pts
20Wapello County57.9-0.4 pts
21Buena Vista County57.8-0.8 pts
22Louisa County57.7-0.3 pts
23Winnebago County57.5-0.2 pts
24Iowa County57.3-0.2 pts
25Clinton County57.3-0.3 pts
26Marion County57.2-0.5 pts
27Boone County57.2-0.8 pts
28Mahaska County57.2-0 pts
29Cerro Gordo County56.9-0.8 pts
30Cedar County56.9-0.5 pts
31Jackson County56.8-0.1 pts
32Des Moines County56.8-0.4 pts
33Bremer County56.7-0.5 pts
34Madison County56.7-0.3 pts
35Mills County56.7-0.3 pts
36Sioux County56.6-0.3 pts
37Worth County56.6-1.2 pts
38Union County56.4-0.5 pts
39Delaware County56.4-0.4 pts
40Lee County56.4-0.5 pts
41Harrison County56.4+0.1 pts
42Page County56.4-0.5 pts
43Fayette County56.4-0.7 pts
44Osceola County56.3-0.2 pts
45Hamilton County56.2-0.5 pts
46Decatur County56.1-1.5 pts
47Calhoun County56.1-0.3 pts
48Plymouth County56-0.3 pts
49Marshall County55.7-0.2 pts
50Clay County55.7-0.6 pts
51Tama County55.6-0.3 pts
52Crawford County55.5-0.5 pts
53Buchanan County55.4-0.3 pts
54Montgomery County55.4-0.2 pts
55Clarke County55.4+0.2 pts
56Monroe County55.4-0.1 pts
57Emmet County55.3-0.8 pts
58Washington County55.2-0.4 pts
59Chickasaw County55.2-0.2 pts
60Keokuk County55.2-0.3 pts
61Grundy County55.1-0.2 pts
62Jefferson County55.1-1.3 pts
63O'Brien County55.1-0.2 pts
64Carroll County55-0.3 pts
65Humboldt County54.9-0.2 pts
66Lucas County54.9-0 pts
67Floyd County54.90 pts
68Adair County54.9-0.7 pts
69Adams County54.9-0.6 pts
70Hardin County54.7-0.4 pts
71Franklin County54.6-0.8 pts
72Appanoose County54.6-0.5 pts
73Clayton County54.6-0.6 pts
74Fremont County54.5-0.4 pts
75Shelby County54.5-0.6 pts
76Greene County54.5-0.1 pts
77Cass County54.5-0.2 pts
78Kossuth County54.3-0.6 pts
79Palo Alto County54.3-0.4 pts
80Hancock County54.1-0.8 pts
81Pocahontas County54.1-0.2 pts
82Audubon County54-0.5 pts
83Howard County53.90 pts
84Guthrie County53.9-0.3 pts
85Van Buren County53.9-0.1 pts
86Dickinson County53.9-0.4 pts
87Allamakee County53.8-0.4 pts
88Cherokee County53.8-0.5 pts
89Butler County53.8-0.3 pts
90Wright County53.7-0.6 pts
91Wayne County53.6+0.3 pts
92Sac County53.5-0.8 pts
93Mitchell County53.4-0.3 pts
94Ida County53.3-0.3 pts
95Lyon County53.2-0.2 pts
96Taylor County53-0.7 pts
97Monona County52.9-0.6 pts
98Davis County52.8-0.2 pts
99Ringgold County51.7+0.4 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, 2019) [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, 2019. 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=2019. 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, 2019. 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=2019.

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, 2019 [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=2019 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_iowa_by_2019,
  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, 2019}},
  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=2019. 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, 2019
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=2019
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/iowa-counties?period=2019.
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 70.3% in 2019, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Ringgold County, with 51.7% in 2019.

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