Counties in Iowa by population aged 18 to 64

Story County had the highest population aged 18 to 64 of 99 counties in 2017, at 71.3%. Ringgold County had the lowest, at 51.3%. The median was 56.6% and the figure for Iowa was 59.7%. Source: the U.S. Census Bureau.

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Highest71.3Story County
Lowest51.3Ringgold County
Median56.699 counties
Iowa59.7History

Map of counties, 2017

Adair County: 56.1 %Adams County: 55.7 %Allamakee County: 54.8 %Appanoose County: 55.7 %Audubon County: 54.9 %Benton County: 58.5 %Black Hawk County: 61.9 %Boone County: 58.4 %Bremer County: 57.6 %Buchanan County: 55.7 %Buena Vista County: 58.8 %Butler County: 54.1 %Calhoun County: 56.7 %Carroll County: 55.7 %Cass County: 55 %Cedar County: 57.5 %Cerro Gordo County: 58 %Cherokee County: 54.8 %Chickasaw County: 55.9 %Clarke County: 55.9 %Clay County: 57 %Clayton County: 55.9 %Clinton County: 57.8 %Crawford County: 56.3 %Dallas County: 59.7 %Davis County: 53.6 %Decatur County: 58.1 %Delaware County: 57.5 %Des Moines County: 57.5 %Dickinson County: 55.1 %Dubuque County: 59.5 %Emmet County: 56.3 %Fayette County: 57.3 %Floyd County: 55.3 %Franklin County: 55.9 %Fremont County: 55.3 %Greene County: 54.8 %Grundy County: 55.6 %Guthrie County: 54.6 %Hamilton County: 56.9 %Hancock County: 55.3 %Hardin County: 56 %Harrison County: 56.6 %Henry County: 60.1 %Howard County: 54.2 %Humboldt County: 55.4 %Ida County: 54.1 %Iowa County: 57.8 %Jackson County: 57 %Jasper County: 58.4 %Jefferson County: 58 %Johnson County: 68.2 %Jones County: 58.5 %Keokuk County: 55.9 %Kossuth County: 55.3 %Lee County: 57.5 %Linn County: 60.9 %Louisa County: 58.6 %Lucas County: 55.8 %Lyon County: 53.7 %Madison County: 57 %Mahaska County: 57.6 %Marion County: 58 %Marshall County: 56.1 %Mills County: 57.6 %Mitchell County: 53.6 %Monona County: 54 %Monroe County: 55.6 %Montgomery County: 55.7 %Muscatine County: 58.8 %O'Brien County: 55.6 %Osceola County: 57.4 %Page County: 57.4 %Palo Alto County: 55.3 %Plymouth County: 56.6 %Pocahontas County: 54.8 %Polk County: 62 %Pottawattamie County: 59.5 %Poweshiek County: 59.4 %Ringgold County: 51.3 %Sac County: 54.7 %Scott County: 60.3 %Shelby County: 55 %Sioux County: 57.2 %Story County: 71.3 %Tama County: 56.1 %Taylor County: 54.3 %Union County: 57.2 %Van Buren County: 54.8 %Wapello County: 59 %Warren County: 58.8 %Washington County: 55.9 %Wayne County: 53.5 %Webster County: 60.2 %Winnebago County: 58 %Winneshiek County: 60.9 %Woodbury County: 59.1 %Worth County: 58.1 %Wright County: 54.4 %
  • Under 55
  • 55 to 56
  • 56 to 57
  • 57 to 58
  • 58 to 59
  • 59 and over
%, 2017. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2017

Story County: 71.3 %Story County71.3Johnson County: 68.2 %Johnson County68.2Polk County: 62 %Polk County62Black Hawk County: 61.9 %Black Hawk County61.9Winneshiek County: 60.9 %Winneshiek County60.9Linn County: 60.9 %Linn County60.9Scott County: 60.3 %Scott County60.3Webster County: 60.2 %Webster County60.2Henry County: 60.1 %Henry County60.1Dallas County: 59.7 %Dallas County59.7Dubuque County: 59.5 %Dubuque County59.5Pottawattamie County: 59.5 %Pottawattamie County59.5Poweshiek County: 59.4 %Poweshiek County59.4Woodbury County: 59.1 %Woodbury County59.1Wapello County: 59 %Wapello County59Muscatine County: 58.8 %Muscatine County58.8Buena Vista County: 58.8 %Buena Vista County58.8Warren County: 58.8 %Warren County58.8Louisa County: 58.6 %Louisa County58.6Jones County: 58.5 %Jones County58.5Benton County: 58.5 %Benton County58.5Jasper County: 58.4 %Jasper County58.4Boone County: 58.4 %Boone County58.4Decatur County: 58.1 %Decatur County58.1Worth County: 58.1 %Worth County58.1Cerro Gordo County: 58 %Cerro Gordo County58Jefferson County: 58 %Jefferson County58Winnebago County: 58 %Winnebago County58Marion County: 58 %Marion County58Iowa County: 57.8 %Iowa County57.8Clinton County: 57.8 %Clinton County57.8Mahaska County: 57.6 %Mahaska County57.6Bremer County: 57.6 %Bremer County57.6Mills County: 57.6 %Mills County57.6Cedar County: 57.5 %Cedar County57.5Des Moines County: 57.5 %Des Moines County57.5Delaware County: 57.5 %Delaware County57.5Lee County: 57.5 %Lee County57.5Page County: 57.4 %Page County57.4Osceola County: 57.4 %Osceola County57.4Story County: 71.3 %Story County71.3Johnson County: 68.2 %Johnson County68.2Polk County: 62 %Polk County62Black Hawk County: 61.9 %Black Hawk County61.9Winneshiek County: 60.9 %Winneshiek County60.9Linn County: 60.9 %Linn County60.9Scott County: 60.3 %Scott County60.3Webster County: 60.2 %Webster County60.2Henry County: 60.1 %Henry County60.1Dallas County: 59.7 %Dallas County59.7Dubuque County: 59.5 %Dubuque County59.5Pottawattamie County: 59.5 %Pottawattamie County59.5Poweshiek County: 59.4 %Poweshiek County59.4Woodbury County: 59.1 %Woodbury County59.1Wapello County: 59 %Wapello County59Muscatine County: 58.8 %Muscatine County58.8Buena Vista County: 58.8 %Buena Vista County58.8Warren County: 58.8 %Warren County58.8Louisa County: 58.6 %Louisa County58.6Jones County: 58.5 %Jones County58.5Benton County: 58.5 %Benton County58.5Jasper County: 58.4 %Jasper County58.4Boone County: 58.4 %Boone County58.4Decatur County: 58.1 %Decatur County58.1Worth County: 58.1 %Worth County58.1Cerro Gordo County: 58 %Cerro Gordo County58Jefferson County: 58 %Jefferson County58Winnebago County: 58 %Winnebago County58Marion County: 58 %Marion County58Iowa County: 57.8 %Iowa County57.8Clinton County: 57.8 %Clinton County57.8Mahaska County: 57.6 %Mahaska County57.6Bremer County: 57.6 %Bremer County57.6Mills County: 57.6 %Mills County57.6Cedar County: 57.5 %Cedar County57.5Des Moines County: 57.5 %Des Moines County57.5Delaware County: 57.5 %Delaware County57.5Lee County: 57.5 %Lee County57.5Page County: 57.4 %Page County57.4Osceola County: 57.4 %Osceola County57.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2017 (%)Change on 2016
1Story County71.3-0.4 pts
2Johnson County68.2-0.5 pts
3Polk County62-0.3 pts
4Black Hawk County61.9-0.7 pts
5Winneshiek County60.9-0.6 pts
6Linn County60.9-0.2 pts
7Scott County60.3-0.3 pts
8Webster County60.2-0.3 pts
9Henry County60.1+0.2 pts
10Dallas County59.7-0.1 pts
11Dubuque County59.5-0.4 pts
12Pottawattamie County59.5-0.4 pts
13Poweshiek County59.4-0.4 pts
14Woodbury County59.1-0.3 pts
15Wapello County59-0.5 pts
16Muscatine County58.8-0.1 pts
17Buena Vista County58.8-0.6 pts
18Warren County58.8-0 pts
19Louisa County58.6-0.2 pts
20Jones County58.5-0.4 pts
21Benton County58.5-0.4 pts
22Jasper County58.4-0.4 pts
23Boone County58.4-0.4 pts
24Decatur County58.1-0.8 pts
25Worth County58.1-0.2 pts
26Cerro Gordo County58-0.6 pts
27Jefferson County58-1.8 pts
28Winnebago County58-0.7 pts
29Marion County58-0.2 pts
30Iowa County57.8-0.6 pts
31Clinton County57.8-0.3 pts
32Mahaska County57.6-0.2 pts
33Bremer County57.6-0.6 pts
34Mills County57.6-0.6 pts
35Cedar County57.5-0.6 pts
36Des Moines County57.5-0.2 pts
37Delaware County57.50 pts
38Lee County57.5-0.8 pts
39Page County57.4-0.2 pts
40Osceola County57.4+0.1 pts
41Fayette County57.3-0.1 pts
42Union County57.2-0.2 pts
43Sioux County57.2-0.5 pts
44Madison County57+0.1 pts
45Clay County57-0.2 pts
46Jackson County57-0.7 pts
47Hamilton County56.9-0 pts
48Calhoun County56.7-0.5 pts
49Harrison County56.6-0.3 pts
50Plymouth County56.6-0.2 pts
51Emmet County56.30 pts
52Crawford County56.30 pts
53Marshall County56.1-0.4 pts
54Tama County56.1-0.5 pts
55Adair County56.1-0.2 pts
56Hardin County56-0.2 pts
57Franklin County55.9-0.5 pts
58Keokuk County55.9-0.2 pts
59Clayton County55.9-0.3 pts
60Chickasaw County55.9-0.4 pts
60Washington County55.9-0.1 pts
62Clarke County55.9-0.3 pts
63Lucas County55.8-0.2 pts
64Montgomery County55.7-0.4 pts
65Carroll County55.7-0.6 pts
66Appanoose County55.7-0.3 pts
67Adams County55.7+0.2 pts
68Buchanan County55.7-0.3 pts
69O'Brien County55.6-0.1 pts
70Grundy County55.6+0.1 pts
71Monroe County55.6-0.8 pts
72Humboldt County55.4-1 pts
73Floyd County55.3-0.2 pts
74Fremont County55.3-0.8 pts
75Hancock County55.3-0.4 pts
76Palo Alto County55.30 pts
77Kossuth County55.3-0.3 pts
78Dickinson County55.1-0.4 pts
79Cass County550 pts
80Shelby County55-0.3 pts
81Audubon County54.9-0.2 pts
82Van Buren County54.8-0.4 pts
83Allamakee County54.8-0.7 pts
84Greene County54.8-0.3 pts
85Pocahontas County54.8-0.1 pts
86Cherokee County54.8-0.8 pts
87Sac County54.7-0.4 pts
88Guthrie County54.60 pts
89Wright County54.4-0.6 pts
90Taylor County54.3-0.1 pts
91Howard County54.2-0.6 pts
92Butler County54.1-0.5 pts
93Ida County54.1-0.5 pts
94Monona County54-0.2 pts
95Lyon County53.7-0.1 pts
96Mitchell County53.6+0.2 pts
97Davis County53.6-0.1 pts
98Wayne County53.5-0.4 pts
99Ringgold County51.3-0.2 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, 2017) [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, 2017. 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=2017. 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, 2017. 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=2017.

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, 2017 [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=2017 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_iowa_by_2017,
  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, 2017}},
  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=2017. 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, 2017
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=2017
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-18-64/iowa-counties?period=2017.
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 71.3% in 2017, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Ringgold County, with 51.3% in 2017.

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