Data / Rankings / Graduate or professional degree, population 25 and over / Counties in Iowa

Counties in Iowa by graduate or professional degree, population 25 and over

Johnson County had the highest graduate or professional degree, population 25 and over of 99 counties in 2021, at 24.4%. Franklin County had the lowest, at 3.2%. The median was 5.9% and the figure for Iowa was 9.7%. Source: the U.S. Census Bureau.

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Highest24.4Johnson County
Lowest3.2Franklin County
Median5.999 counties
Iowa9.7History

Map of counties, 2021

Adair County: 5.3 %Adams County: 4.2 %Allamakee County: 5.4 %Appanoose County: 5 %Audubon County: 5.5 %Benton County: 7 %Black Hawk County: 10.2 %Boone County: 6.6 %Bremer County: 11.5 %Buchanan County: 6.2 %Buena Vista County: 6.8 %Butler County: 4.2 %Calhoun County: 6.5 %Carroll County: 5.2 %Cass County: 5.9 %Cedar County: 6 %Cerro Gordo County: 7.7 %Cherokee County: 7.1 %Chickasaw County: 5.4 %Clarke County: 4.2 %Clay County: 6.7 %Clayton County: 4.3 %Clinton County: 5.9 %Crawford County: 4.1 %Dallas County: 16.2 %Davis County: 5.1 %Decatur County: 12 %Delaware County: 5.2 %Des Moines County: 7.3 %Dickinson County: 7.3 %Dubuque County: 11.1 %Emmet County: 4.4 %Fayette County: 4.8 %Floyd County: 5.5 %Franklin County: 3.2 %Fremont County: 3.2 %Greene County: 5 %Grundy County: 6.4 %Guthrie County: 6 %Hamilton County: 6 %Hancock County: 3.5 %Hardin County: 5.1 %Harrison County: 5.4 %Henry County: 7 %Howard County: 4.7 %Humboldt County: 3.4 %Ida County: 4.2 %Iowa County: 6.4 %Jackson County: 6.1 %Jasper County: 5.8 %Jefferson County: 16.4 %Johnson County: 24.4 %Jones County: 6.4 %Keokuk County: 5 %Kossuth County: 4.9 %Lee County: 5.4 %Linn County: 10.7 %Louisa County: 4.4 %Lucas County: 3.6 %Lyon County: 4.2 %Madison County: 7.5 %Mahaska County: 5.8 %Marion County: 9.7 %Marshall County: 6.4 %Mills County: 9 %Mitchell County: 5.6 %Monona County: 4 %Monroe County: 4.4 %Montgomery County: 4.4 %Muscatine County: 7 %O'Brien County: 4.8 %Osceola County: 4.9 %Page County: 5 %Palo Alto County: 6.8 %Plymouth County: 6.6 %Pocahontas County: 3.9 %Polk County: 11.9 %Pottawattamie County: 7.3 %Poweshiek County: 12.8 %Ringgold County: 6.7 %Sac County: 4.1 %Scott County: 12.4 %Shelby County: 5.4 %Sioux County: 8.8 %Story County: 21.1 %Tama County: 5 %Taylor County: 4.3 %Union County: 6.7 %Van Buren County: 6.2 %Wapello County: 7 %Warren County: 9.7 %Washington County: 7.2 %Wayne County: 4.7 %Webster County: 5.7 %Winnebago County: 6.2 %Winneshiek County: 12.1 %Woodbury County: 7.4 %Worth County: 6 %Wright County: 4.2 %
  • Under 4.3
  • 4.3 to 5.1
  • 5.1 to 5.9
  • 5.9 to 6.7
  • 6.7 to 8.4
  • 8.4 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

Johnson County: 24.4 %Johnson County24.4Story County: 21.1 %Story County21.1Jefferson County: 16.4 %Jefferson County16.4Dallas County: 16.2 %Dallas County16.2Poweshiek County: 12.8 %Poweshiek County12.8Scott County: 12.4 %Scott County12.4Winneshiek County: 12.1 %Winneshiek County12.1Decatur County: 12 %Decatur County12Polk County: 11.9 %Polk County11.9Bremer County: 11.5 %Bremer County11.5Dubuque County: 11.1 %Dubuque County11.1Linn County: 10.7 %Linn County10.7Black Hawk County: 10.2 %Black Hawk County10.2Marion County: 9.7 %Marion County9.7Warren County: 9.7 %Warren County9.7Mills County: 9 %Mills County9Sioux County: 8.8 %Sioux County8.8Cerro Gordo County: 7.7 %Cerro Gordo County7.7Madison County: 7.5 %Madison County7.5Woodbury County: 7.4 %Woodbury County7.4Des Moines County: 7.3 %Des Moines County7.3Pottawattamie County: 7.3 %Pottawattamie County7.3Dickinson County: 7.3 %Dickinson County7.3Washington County: 7.2 %Washington County7.2Cherokee County: 7.1 %Cherokee County7.1Muscatine County: 7 %Muscatine County7Benton County: 7 %Benton County7Henry County: 7 %Henry County7Wapello County: 7 %Wapello County7Buena Vista County: 6.8 %Buena Vista County6.8Palo Alto County: 6.8 %Palo Alto County6.8Clay County: 6.7 %Clay County6.7Ringgold County: 6.7 %Ringgold County6.7Union County: 6.7 %Union County6.7Boone County: 6.6 %Boone County6.6Plymouth County: 6.6 %Plymouth County6.6Calhoun County: 6.5 %Calhoun County6.5Iowa County: 6.4 %Iowa County6.4Marshall County: 6.4 %Marshall County6.4Grundy County: 6.4 %Grundy County6.4Johnson County: 24.4 %Johnson County24.4Story County: 21.1 %Story County21.1Jefferson County: 16.4 %Jefferson County16.4Dallas County: 16.2 %Dallas County16.2Poweshiek County: 12.8 %Poweshiek County12.8Scott County: 12.4 %Scott County12.4Winneshiek County: 12.1 %Winneshiek County12.1Decatur County: 12 %Decatur County12Polk County: 11.9 %Polk County11.9Bremer County: 11.5 %Bremer County11.5Dubuque County: 11.1 %Dubuque County11.1Linn County: 10.7 %Linn County10.7Black Hawk County: 10.2 %Black Hawk County10.2Marion County: 9.7 %Marion County9.7Warren County: 9.7 %Warren County9.7Mills County: 9 %Mills County9Sioux County: 8.8 %Sioux County8.8Cerro Gordo County: 7.7 %Cerro Gordo County7.7Madison County: 7.5 %Madison County7.5Woodbury County: 7.4 %Woodbury County7.4Des Moines County: 7.3 %Des Moines County7.3Pottawattamie County: 7.3 %Pottawattamie County7.3Dickinson County: 7.3 %Dickinson County7.3Washington County: 7.2 %Washington County7.2Cherokee County: 7.1 %Cherokee County7.1Muscatine County: 7 %Muscatine County7Benton County: 7 %Benton County7Henry County: 7 %Henry County7Wapello County: 7 %Wapello County7Buena Vista County: 6.8 %Buena Vista County6.8Palo Alto County: 6.8 %Palo Alto County6.8Clay County: 6.7 %Clay County6.7Ringgold County: 6.7 %Ringgold County6.7Union County: 6.7 %Union County6.7Boone County: 6.6 %Boone County6.6Plymouth County: 6.6 %Plymouth County6.6Calhoun County: 6.5 %Calhoun County6.5Iowa County: 6.4 %Iowa County6.4Marshall County: 6.4 %Marshall County6.4Grundy County: 6.4 %Grundy County6.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2021 (%)
1Johnson County24.4
2Story County21.1
3Jefferson County16.4
4Dallas County16.2
5Poweshiek County12.8
6Scott County12.4
7Winneshiek County12.1
8Decatur County12
9Polk County11.9
10Bremer County11.5
11Dubuque County11.1
12Linn County10.7
13Black Hawk County10.2
14Marion County9.7
15Warren County9.7
16Mills County9
17Sioux County8.8
18Cerro Gordo County7.7
19Madison County7.5
20Woodbury County7.4
21Des Moines County7.3
22Pottawattamie County7.3
23Dickinson County7.3
24Washington County7.2
25Cherokee County7.1
26Muscatine County7
27Benton County7
28Henry County7
28Wapello County7
30Buena Vista County6.8
31Palo Alto County6.8
32Clay County6.7
32Ringgold County6.7
34Union County6.7
35Boone County6.6
36Plymouth County6.6
37Calhoun County6.5
38Iowa County6.4
39Marshall County6.4
40Grundy County6.4
40Jones County6.4
42Buchanan County6.2
43Winnebago County6.2
44Van Buren County6.2
45Jackson County6.1
46Hamilton County6
47Worth County6
48Cedar County6
48Guthrie County6
50Clinton County5.9
51Cass County5.9
52Jasper County5.8
53Mahaska County5.8
54Webster County5.7
55Mitchell County5.6
56Audubon County5.5
57Floyd County5.5
58Lee County5.4
58Shelby County5.4
60Harrison County5.4
61Allamakee County5.4
61Chickasaw County5.4
63Adair County5.3
64Carroll County5.2
65Delaware County5.2
66Hardin County5.1
67Davis County5.1
68Appanoose County5
69Keokuk County5
70Page County5
70Tama County5
72Greene County5
73Kossuth County4.9
73Osceola County4.9
75O'Brien County4.8
76Fayette County4.8
77Howard County4.7
78Wayne County4.7
79Monroe County4.4
80Emmet County4.4
81Louisa County4.4
81Montgomery County4.4
83Taylor County4.3
84Clayton County4.3
85Adams County4.2
86Lyon County4.2
87Clarke County4.2
87Wright County4.2
89Butler County4.2
90Ida County4.2
91Crawford County4.1
92Sac County4.1
93Monona County4
94Pocahontas County3.9
95Lucas County3.6
96Hancock County3.5
97Humboldt County3.4
98Fremont County3.2
99Franklin County3.2

Other periods

About this ranking

People aged 25 and over whose highest degree is a master's, professional school or doctorate degree, as a percentage of all people aged 25 and over. United States: American Community Survey five-year estimate, where the period shown is the last year of the five-year span.

A subset of bachelors_degree_share, which also counts people whose highest degree is a bachelor's.

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. American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat. 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). American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs (Counties in Iowa by graduate or professional degree, population 25 and over, 2021) [Data set]. Retrieved October 12, 2026, from https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat

MLA 9

American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs, Counties in Iowa by graduate or professional degree, population 25 and over, 2021. U.S. Census Bureau, 29 Jan. 2026, https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat. Invokely, https://invokely.ai/rankings/graduate-or-professional-degree/iowa-counties?period=2021. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs. Counties in Iowa by graduate or professional degree, population 25 and over, 2021. Dataset. Accessed October 12, 2026. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat. Also distributed by Invokely, https://invokely.ai/rankings/graduate-or-professional-degree/iowa-counties?period=2021.

Harvard

U.S. Census Bureau (2026) American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs, Counties in Iowa by graduate or professional degree, population 25 and over, 2021 [Dataset]. Available at: https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat, via Invokely: https://invokely.ai/rankings/graduate-or-professional-degree/iowa-counties?period=2021 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_iowa_by_2021,
  author = {{U.S. Census Bureau}},
  title = {{American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs: Counties in Iowa by graduate or professional degree, population 25 and over, 2021}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/graduate-or-professional-degree/iowa-counties?period=2021. Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary\_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs: Counties in Iowa by graduate or professional degree, population 25 and over, 2021
PY  - 2026
DA  - 2026/01/29
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat
L2  - https://invokely.ai/rankings/graduate-or-professional-degree/iowa-counties?period=2021
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/graduate-or-professional-degree/iowa-counties?period=2021.
N1  - Publisher attribution: U.S. Census Bureau. American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs. https://www2.census.gov/programs-surveys/acs/summary_file/2021/table-based-SF/data/5YRData/acsdt5y2021-b15003.dat. Retrieved 2026-10-12.
ER  -
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Rank Counties in Iowa by graduate or professional degree, population 25 and over using official data, and cite the source.
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Questions

Which county has the highest graduate or professional degree, population 25 and over?

Johnson County, with 24.4% in 2021, according to the U.S. Census Bureau.

Which county has the lowest graduate or professional degree, population 25 and over?

Franklin County, with 3.2% 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, American Community Survey 5-year estimates, table B15003: population 25 years and over with a master's, professional school or doctorate degree as a percentage of the population 25 years and over, calculated with stored inputs. Retrieved 2026-10-12.

Graduate or professional degree, population 25 and over: other rankings

Counties in Iowa: more rankings