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 2015, at 72%. Ringgold County had the lowest, at 51.7%. The median was 57.2% and the figure for Iowa was 60.3%. Source: the U.S. Census Bureau.

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Highest72Story County
Lowest51.7Ringgold County
Median57.299 counties
Iowa60.3History

Map of counties, 2015

Adair County: 56.6 %Adams County: 56.2 %Allamakee County: 56.1 %Appanoose County: 56.2 %Audubon County: 55.3 %Benton County: 59 %Black Hawk County: 63 %Boone County: 59.1 %Bremer County: 58.7 %Buchanan County: 56.2 %Buena Vista County: 60 %Butler County: 54.9 %Calhoun County: 57.3 %Carroll County: 56.5 %Cass County: 55.5 %Cedar County: 58.2 %Cerro Gordo County: 59.1 %Cherokee County: 55.9 %Chickasaw County: 56.8 %Clarke County: 57.5 %Clay County: 57.4 %Clayton County: 56.4 %Clinton County: 58.4 %Crawford County: 56.5 %Dallas County: 59.7 %Davis County: 53.7 %Decatur County: 59.9 %Delaware County: 57.8 %Des Moines County: 58 %Dickinson County: 56 %Dubuque County: 60.3 %Emmet County: 57.3 %Fayette County: 58.1 %Floyd County: 55.7 %Franklin County: 56.7 %Fremont County: 55.9 %Greene County: 55.2 %Grundy County: 56.1 %Guthrie County: 55.3 %Hamilton County: 57.2 %Hancock County: 56.1 %Hardin County: 56.3 %Harrison County: 57.7 %Henry County: 59.6 %Howard County: 55.1 %Humboldt County: 56.9 %Ida County: 54.8 %Iowa County: 58.4 %Jackson County: 58 %Jasper County: 59.1 %Jefferson County: 61.5 %Johnson County: 69.1 %Jones County: 59.3 %Keokuk County: 56.2 %Kossuth County: 55.9 %Lee County: 58.6 %Linn County: 61.3 %Louisa County: 58.9 %Lucas County: 55.9 %Lyon County: 54.2 %Madison County: 57 %Mahaska County: 58.5 %Marion County: 58.5 %Marshall County: 57 %Mills County: 58.4 %Mitchell County: 53.8 %Monona County: 54.5 %Monroe County: 56.7 %Montgomery County: 56.5 %Muscatine County: 59.2 %O'Brien County: 55.7 %Osceola County: 57.2 %Page County: 57.9 %Palo Alto County: 55.8 %Plymouth County: 57.2 %Pocahontas County: 55.2 %Polk County: 62.5 %Pottawattamie County: 60.4 %Poweshiek County: 60.4 %Ringgold County: 51.7 %Sac County: 55 %Scott County: 61.1 %Shelby County: 55.5 %Sioux County: 58 %Story County: 72 %Tama County: 56.8 %Taylor County: 54.7 %Union County: 57.6 %Van Buren County: 55.6 %Wapello County: 60 %Warren County: 59.2 %Washington County: 56.3 %Wayne County: 54.1 %Webster County: 60.8 %Winnebago County: 58.7 %Winneshiek County: 62.2 %Woodbury County: 59.7 %Worth County: 58.4 %Wright County: 55.4 %
  • Under 55
  • 55 to 56
  • 56 to 57
  • 57 to 58
  • 58 to 60
  • 60 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

Story County: 72 %Story County72Johnson County: 69.1 %Johnson County69.1Black Hawk County: 63 %Black Hawk County63Polk County: 62.5 %Polk County62.5Winneshiek County: 62.2 %Winneshiek County62.2Jefferson County: 61.5 %Jefferson County61.5Linn County: 61.3 %Linn County61.3Scott County: 61.1 %Scott County61.1Webster County: 60.8 %Webster County60.8Pottawattamie County: 60.4 %Pottawattamie County60.4Poweshiek County: 60.4 %Poweshiek County60.4Dubuque County: 60.3 %Dubuque County60.3Buena Vista County: 60 %Buena Vista County60Wapello County: 60 %Wapello County60Decatur County: 59.9 %Decatur County59.9Woodbury County: 59.7 %Woodbury County59.7Dallas County: 59.7 %Dallas County59.7Henry County: 59.6 %Henry County59.6Jones County: 59.3 %Jones County59.3Muscatine County: 59.2 %Muscatine County59.2Warren County: 59.2 %Warren County59.2Boone County: 59.1 %Boone County59.1Cerro Gordo County: 59.1 %Cerro Gordo County59.1Jasper County: 59.1 %Jasper County59.1Benton County: 59 %Benton County59Louisa County: 58.9 %Louisa County58.9Bremer County: 58.7 %Bremer County58.7Winnebago County: 58.7 %Winnebago County58.7Lee County: 58.6 %Lee County58.6Marion County: 58.5 %Marion County58.5Mahaska County: 58.5 %Mahaska County58.5Mills County: 58.4 %Mills County58.4Iowa County: 58.4 %Iowa County58.4Worth County: 58.4 %Worth County58.4Clinton County: 58.4 %Clinton County58.4Cedar County: 58.2 %Cedar County58.2Fayette County: 58.1 %Fayette County58.1Sioux County: 58 %Sioux County58Jackson County: 58 %Jackson County58Des Moines County: 58 %Des Moines County58Story County: 72 %Story County72Johnson County: 69.1 %Johnson County69.1Black Hawk County: 63 %Black Hawk County63Polk County: 62.5 %Polk County62.5Winneshiek County: 62.2 %Winneshiek County62.2Jefferson County: 61.5 %Jefferson County61.5Linn County: 61.3 %Linn County61.3Scott County: 61.1 %Scott County61.1Webster County: 60.8 %Webster County60.8Pottawattamie County: 60.4 %Pottawattamie County60.4Poweshiek County: 60.4 %Poweshiek County60.4Dubuque County: 60.3 %Dubuque County60.3Buena Vista County: 60 %Buena Vista County60Wapello County: 60 %Wapello County60Decatur County: 59.9 %Decatur County59.9Woodbury County: 59.7 %Woodbury County59.7Dallas County: 59.7 %Dallas County59.7Henry County: 59.6 %Henry County59.6Jones County: 59.3 %Jones County59.3Muscatine County: 59.2 %Muscatine County59.2Warren County: 59.2 %Warren County59.2Boone County: 59.1 %Boone County59.1Cerro Gordo County: 59.1 %Cerro Gordo County59.1Jasper County: 59.1 %Jasper County59.1Benton County: 59 %Benton County59Louisa County: 58.9 %Louisa County58.9Bremer County: 58.7 %Bremer County58.7Winnebago County: 58.7 %Winnebago County58.7Lee County: 58.6 %Lee County58.6Marion County: 58.5 %Marion County58.5Mahaska County: 58.5 %Mahaska County58.5Mills County: 58.4 %Mills County58.4Iowa County: 58.4 %Iowa County58.4Worth County: 58.4 %Worth County58.4Clinton County: 58.4 %Clinton County58.4Cedar County: 58.2 %Cedar County58.2Fayette County: 58.1 %Fayette County58.1Sioux County: 58 %Sioux County58Jackson County: 58 %Jackson County58Des Moines County: 58 %Des Moines County58
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2015 (%)Change on 2014
1Story County72-0.1 pts
2Johnson County69.1-0.4 pts
3Black Hawk County63-0.4 pts
4Polk County62.5-0.3 pts
5Winneshiek County62.2-0.4 pts
6Jefferson County61.5-1.9 pts
7Linn County61.3-0.3 pts
8Scott County61.1-0.3 pts
9Webster County60.8-0.3 pts
10Pottawattamie County60.4-0.3 pts
11Poweshiek County60.4-0.4 pts
12Dubuque County60.3-0.3 pts
13Buena Vista County60+0.1 pts
14Wapello County60-0.1 pts
15Decatur County59.9+0.3 pts
16Woodbury County59.7-0.2 pts
17Dallas County59.7-0.3 pts
18Henry County59.6-0.3 pts
19Jones County59.3-0.6 pts
20Muscatine County59.2-0.3 pts
21Warren County59.2-0.3 pts
22Boone County59.1-0.1 pts
23Cerro Gordo County59.1-0.6 pts
24Jasper County59.1-0.2 pts
25Benton County59-0.3 pts
26Louisa County58.9-0.7 pts
27Bremer County58.7-0.4 pts
28Winnebago County58.7-0 pts
29Lee County58.6-0.6 pts
30Marion County58.5-0.5 pts
31Mahaska County58.5-0.5 pts
32Mills County58.4-1.1 pts
33Iowa County58.4-0.3 pts
33Worth County58.4+0.5 pts
35Clinton County58.4-0.6 pts
36Cedar County58.2-0.4 pts
37Fayette County58.1-0.2 pts
38Sioux County58-0.3 pts
39Jackson County58-0 pts
40Des Moines County58-0.2 pts
41Page County57.9-0.3 pts
42Delaware County57.8-0.2 pts
43Harrison County57.7-0.4 pts
44Union County57.6-0.5 pts
45Clarke County57.5-0.4 pts
46Clay County57.4-0.1 pts
47Emmet County57.3-0.6 pts
48Calhoun County57.3-0.1 pts
49Plymouth County57.2+0.1 pts
50Osceola County57.2+0.2 pts
51Hamilton County57.2-0.3 pts
52Madison County57+0.1 pts
53Marshall County57-0.4 pts
54Humboldt County56.9+0.1 pts
55Tama County56.8-0 pts
56Chickasaw County56.8+0.1 pts
57Monroe County56.7+0.1 pts
58Franklin County56.7-0.3 pts
59Adair County56.6+0.6 pts
60Carroll County56.5-0.4 pts
61Montgomery County56.50 pts
62Crawford County56.5-0.2 pts
63Clayton County56.4-0.3 pts
64Hardin County56.3-0.1 pts
65Washington County56.3-0.3 pts
66Appanoose County56.2-0.1 pts
67Keokuk County56.2-0 pts
68Buchanan County56.2-0.5 pts
69Adams County56.2+0.5 pts
70Hancock County56.1-0.5 pts
71Allamakee County56.1-0.6 pts
72Grundy County56.1-0 pts
73Dickinson County56-0.8 pts
74Fremont County55.9-0.2 pts
75Cherokee County55.9-0.8 pts
76Kossuth County55.9-0.1 pts
76Lucas County55.9+0.1 pts
78Palo Alto County55.8-0.4 pts
79Floyd County55.7-0.5 pts
80O'Brien County55.7+0.1 pts
81Van Buren County55.6-0.3 pts
82Shelby County55.5+0.3 pts
83Cass County55.5-0.6 pts
84Wright County55.4-0.4 pts
85Guthrie County55.3-0.2 pts
86Audubon County55.3-0.2 pts
87Pocahontas County55.2-0.2 pts
88Greene County55.2-0.3 pts
89Howard County55.1-0.2 pts
90Sac County55-0.5 pts
91Butler County54.9-0.3 pts
92Ida County54.8-0.3 pts
93Taylor County54.7-0.7 pts
94Monona County54.5+0.2 pts
95Lyon County54.2-0.5 pts
96Wayne County54.1+0.2 pts
97Mitchell County53.8-0.1 pts
98Davis County53.7-0.2 pts
99Ringgold County51.7-0 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, 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 Iowa 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/iowa-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 Iowa 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/iowa-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 Iowa 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/iowa-counties?period=2015 (Accessed: 12 October 2026).

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

Story County, with 72% in 2015, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Ringgold County, with 51.7% 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 Iowa: more rankings