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

Counties in Iowa by population aged 18 to 64, 2025

Story County had the highest population aged 18 to 64 of 99 counties in 2025, at 69.1%. Ringgold County had the lowest, at 49.8%. The median was 53.8% and the figure for Iowa was 57.7%. Source: the U.S. Census Bureau.

Highest69.1Story County
Lowest49.8Ringgold County
Median53.899 counties
Iowa57.7History

Top 40 counties, 2025

Story County: 69.1 %Story County69.1Johnson County: 65.7 %Johnson County65.7Polk County: 60.8 %Polk County60.8Dallas County: 60 %Dallas County60Linn County: 59.1 %Linn County59.1Black Hawk County: 59 %Black Hawk County59Scott County: 58.3 %Scott County58.3Woodbury County: 58.2 %Woodbury County58.2Warren County: 57.6 %Warren County57.6Webster County: 57.5 %Webster County57.5Pottawattamie County: 57.4 %Pottawattamie County57.4Muscatine County: 57.4 %Muscatine County57.4Wapello County: 57.3 %Wapello County57.3Jones County: 57.1 %Jones County57.1Henry County: 57.1 %Henry County57.1Jasper County: 56.9 %Jasper County56.9Poweshiek County: 56.9 %Poweshiek County56.9Dubuque County: 56.9 %Dubuque County56.9Boone County: 56.7 %Boone County56.7Union County: 56.4 %Union County56.4Louisa County: 56.2 %Louisa County56.2Buena Vista County: 56.1 %Buena Vista County56.1Cedar County: 55.9 %Cedar County55.9Marion County: 55.9 %Marion County55.9Bremer County: 55.8 %Bremer County55.8Page County: 55.8 %Page County55.8Osceola County: 55.8 %Osceola County55.8Benton County: 55.8 %Benton County55.8Sioux County: 55.7 %Sioux County55.7Madison County: 55.7 %Madison County55.7Mahaska County: 55.6 %Mahaska County55.6Des Moines County: 55.5 %Des Moines County55.5Mills County: 55.3 %Mills County55.3Decatur County: 55.3 %Decatur County55.3Marshall County: 55.3 %Marshall County55.3Winneshiek County: 55.1 %Winneshiek County55.1Clinton County: 55 %Clinton County55Winnebago County: 54.8 %Winnebago County54.8Monroe County: 54.7 %Monroe County54.7Hardin County: 54.6 %Hardin County54.6
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2025 (%)Change on 2024
1Story County69.1-0.2 pts
2Johnson County65.7-0.4 pts
3Polk County60.8-0.1 pts
4Dallas County60-0.1 pts
5Linn County59.1-0.2 pts
6Black Hawk County59-0.2 pts
7Scott County58.3-0.1 pts
8Woodbury County58.2-0 pts
9Warren County57.6+0.1 pts
10Webster County57.5-0.2 pts
11Pottawattamie County57.4-0.1 pts
12Muscatine County57.4+0.1 pts
13Wapello County57.3+0.1 pts
14Jones County57.1-0.3 pts
15Henry County57.1-0.2 pts
16Jasper County56.9-0.3 pts
17Poweshiek County56.9-0.7 pts
18Dubuque County56.9-0.2 pts
19Boone County56.7+0.2 pts
20Union County56.4+0.4 pts
21Louisa County56.2-0.6 pts
22Buena Vista County56.1-0.2 pts
23Cedar County55.9-0.2 pts
24Marion County55.9-0 pts
25Bremer County55.8-0 pts
26Page County55.8+0.2 pts
27Osceola County55.8+0.1 pts
28Benton County55.8-0.6 pts
29Sioux County55.7-0 pts
30Madison County55.7-0.1 pts
31Mahaska County55.6-0.2 pts
32Des Moines County55.5-0.1 pts
33Mills County55.3-0.2 pts
34Decatur County55.3-0.2 pts
35Marshall County55.3-0 pts
36Winneshiek County55.1-0.6 pts
37Clinton County55-0.4 pts
38Winnebago County54.8-0.4 pts
39Monroe County54.7-0.1 pts
40Hardin County54.6+0.2 pts
41Clarke County54.5+0.4 pts
42Iowa County54.5-0.5 pts
43Plymouth County54.3-0.3 pts
44Crawford County54.1+0.1 pts
45Harrison County54-0.6 pts
46Fayette County54-0.5 pts
47Emmet County53.9+0.2 pts
48O'Brien County53.90 pts
49Cerro Gordo County53.8-0.4 pts
50Tama County53.8-0.4 pts
51Appanoose County53.7+0.1 pts
52Lyon County53.7+0.3 pts
53Lee County53.6-0.4 pts
54Buchanan County53.6-0.3 pts
55Clay County53.6-0.5 pts
56Jackson County53.5-0.5 pts
57Keokuk County53.50 pts
58Delaware County53.4-0.5 pts
59Montgomery County53.40 pts
60Franklin County53.3+0.1 pts
61Floyd County53.3+0.1 pts
62Washington County53.2-0.4 pts
63Worth County53.2-0.2 pts
64Hamilton County53.2-0.6 pts
65Fremont County53.1-0 pts
66Calhoun County53-0.4 pts
67Adair County53-0.1 pts
68Grundy County53-0 pts
69Carroll County52.8-0.3 pts
70Wright County52.8+0.3 pts
71Ida County52.8-0 pts
72Chickasaw County52.5-0.2 pts
73Lucas County52.3-0.4 pts
74Humboldt County52.3-0.8 pts
75Howard County52.3-0.6 pts
76Adams County52.3-0.9 pts
77Cass County52.3-0.1 pts
78Taylor County52.20 pts
79Shelby County52.1-0.6 pts
80Palo Alto County52.1-0.4 pts
81Monona County51.8-0.3 pts
82Mitchell County51.8+0.1 pts
83Guthrie County51.7-0.6 pts
84Greene County51.7-0.1 pts
85Butler County51.6-0 pts
86Hancock County51.6-0.2 pts
87Sac County51.4-0.4 pts
88Kossuth County51.4-0.3 pts
89Jefferson County51.4-0.4 pts
90Wayne County51.3+0.1 pts
91Pocahontas County51.2-0.4 pts
92Dickinson County51.1-0.1 pts
93Clayton County50.9-0.3 pts
94Audubon County50.9-0.5 pts
95Allamakee County50.9-0.2 pts
96Cherokee County50.6-0.2 pts
97Van Buren County50.5-0.5 pts
98Davis County50.4-0.6 pts
99Ringgold County49.8-0.2 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.

Use this data in your AI agent

Invokely serves this figure to AI assistants through MCP and to code through a REST API, with the source and citation attached. Ask your assistant:

Rank Counties in Iowa by population aged 18 to 64 using official data, and cite the source.
rank_places {"indicator":"population_18_64_share","level":"province","within":"Iowa","limit":10}
GET https://invokely.ai/api/v1/rank?indicator=population_18_64_share&level=province&within=Iowa&limit=10

Connect Claude, ChatGPT or Cursor in one step. The trial answers 25 calls a day without an account.

Questions

Which county has the highest population aged 18 to 64?

Story County, with 69.1% in 2025, according to the U.S. Census Bureau.

Which county has the lowest population aged 18 to 64?

Ringgold County, with 49.8% in 2025.

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