Polk County, Iowa

Polk County, Iowa
County
The Polk County Courthouse in Des Moines
Flag
Seal
Location within the U.S. state of Iowa
Coordinates: 41°41′05″N 93°34′08″W / 41.684816°N 93.568971°W / 41.684816; -93.568971
Country United States
State Iowa
FoundedJanuary 13, 1846 (created)
March 1, 1846 (organized)
Named afterJames K. Polk
SeatDes Moines
Largest cityDes Moines
Area
 • Total
591.888 sq mi (1,532.98 km2)
 • Land572.720 sq mi (1,483.34 km2)
 • Water19.168 sq mi (49.64 km2)  3.24%
Population
 (2020)
 • Total
492,401
 • Estimate 
(2024)
516,185
 • Density859.759/sq mi (331.955/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Area code515
Congressional district3rd
Websitepolkcountyiowa.gov
  • Iowa county number 77[1]

Polk County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 492,401,[2] and was estimated to be 516,185 in 2024,[3] making it the most populous county in Iowa. The county seat and the largest city is Des Moines,[4] which is also the capital city of Iowa. Polk County is included in the Des Moines–West Des Moines, IA Metropolitan Statistical Area.

History

Polk County was formed on January 13, 1846 and organized on March 1, 1846.[5], the legislative body of the Iowa Territory authorized the creation of twelve counties in the Territory,[6] with general descriptions of their boundaries. On January 17 they further enacted a resolution setting the effective date of the county government for Jasper and Polk Counties as March 1, 1846.[7][8] Polk County's name referred to United States President James K. Polk, who served from 1845 to 1849.

The first courthouse, a two-story structure, was built in Des Moines in 1846. Rapid settlement and commercial growth in the county soon rendered this building insufficient, so construction of a larger building was initiated in 1858. Due to construction delays and the onset of the Civil War, the structure was not completed until 1866. The present courthouse was erected in 1906, and in 1962 it was extensively renovated and enlarged.[9]

Geography

According to the United States Census Bureau, the county has a total area of 591.888 square miles (1,532.98 km2), of which 572.720 square miles (1,483.34 km2) is land and 19.168 square miles (49.64 km2) (3.24%) is water.[10] It is the 41st-largest county in Iowa by total area[11] The county is bisected by the Des Moines River.

Major highways

Transit

Demographics

Historical population
CensusPop.Note%±
18504,513—
186011,625157.6%
187027,857139.6%
188042,39552.2%
189065,41054.3%
190082,62426.3%
1910110,43833.7%
1920154,02939.5%
1930172,83712.2%
1940195,83513.3%
1950226,01015.4%
1960266,31517.8%
1970286,1017.4%
1980303,1706.0%
1990327,1407.9%
2000374,60114.5%
2010430,64015.0%
2020492,40114.3%
2024 (est.)516,185[12] 4.8%
U.S. Decennial Census[13]
1790–1960[14] 1900–1990[15]
1990–2000[16] 2010–2020[3]

As of the second quarter of 2025, the median home value in Polk County was $293,337.[17]

As of the 2024 American Community Survey, there are 211,294 estimated households in Polk County with an average of 2.40 persons per household. The county has a median household income of $82,405. Approximately 9.9% of the county's population lives at or below the poverty line. Polk County has an estimated 69.4% employment rate, with 41.5% of the population holding a bachelor's degree or higher and 92.4% holding a high school diploma.[3] There were 224,898 housing units at an average density of 392.68 per square mile (151.6/km2).

The top five reported languages (people were allowed to report up to two languages, thus the figures will generally add to more than 100%) were English (85.0%), Spanish (6.6%), Indo-European (3.2%), Asian and Pacific Islander (3.4%), and Other (1.9%).

The median age in the county was 36.2 years.

Polk County, Iowa – racial and ethnic composition
Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.
Race / ethnicity (NH = non-Hispanic) Pop. 1980[18] Pop. 1990[19] Pop. 2000[20] Pop. 2010[21] Pop. 2020[22]
White alone (NH) 280,143
(92.40%)		 299,469
(91.54%)		 323,785
(86.43%)		 347,710
(80.74%)		 362,260
(73.57%)
Black or African American alone (NH) 13,570
(4.48%)		 14,618
(4.47%)		 17,874
(4.77%)		 25,344
(5.89%)		 34,990
(7.11%)
Native American or Alaska Native alone (NH) 712
(0.23%)		 834
(0.25%)		 878
(0.23%)		 894
(0.21%)		 1,081
(0.22%)
Asian alone (NH) 2,204
(0.73%)		 5,871
(1.79%)		 9,765
(2.61%)		 15,118
(3.51%)		 24,313
(4.94%)
Pacific Islander alone (NH) — — 178
(0.05%)		 228
(0.05%)		 280
(0.06%)
Other race alone (NH) 1,962
(0.65%)		 187
(0.06%)		 554
(0.15%)		 605
(0.14%)		 1,713
(0.35%)
Mixed race or multiracial (NH) — — 5,077
(1.36%)		 8,094
(1.88%)		 19,709
(4.00%)
Hispanic or Latino (any race) 4,579
(1.51%)		 6,161
(1.88%)		 16,490
(4.40%)		 32,647
(7.58%)		 48,055
(9.76%)
Total 303,170
(100.00%)		 327,140
(100.00%)		 374,601
(100.00%)		 430,640
(100.00%)		 492,401
(100.00%)

2024 estimate

As of the 2024 estimate, there were 516,185 people, 211,294 households, and _ families residing in the county. The population density was 901.29 inhabitants per square mile (348.0/km2). There were 224,898 housing units at an average density of 392.68 per square mile (151.6/km2). The racial makeup of the county was 82.8% White (72.7% NH White), 8.2% African American, 0.6% Native American, 5.5% Asian, 0.1% Pacific Islander, _% from some other races and 2.8% from two or more races. Hispanic or Latino people of any race were 11.2% of the population.

2020 census

As of the 2020 census, there were 492,401 people, 196,891 households, and 121,993 families residing in the county.[23] The population density was 859.76 inhabitants per square mile (332.0/km2). There were 210,184 housing units at an average density of 366.99 per square mile (141.7/km2). The racial makeup of the county was 75.93% White, 7.23% African American, 0.46% Native American, 4.98% Asian, 0.06% Pacific Islander, 3.88% from some other races and 7.45% from two or more races. Hispanic or Latino people of any race were 9.76% of the population.[24]

The median age was 36.0 years. 24.5% of residents were under the age of 18 and 14.1% of residents were 65 years of age or older. For every 100 females there were 96.6 males, and for every 100 females age 18 and over there were 94.6 males age 18 and over.[25][26]

95.5% of residents lived in urban areas, while 4.5% lived in rural areas.[27]

There were 196,891 households in the county, of which 31.1% had children under the age of 18 living in them. Of all households, 45.9% were married-couple households, 19.7% were households with a male householder and no spouse or partner present, and 26.7% were households with a female householder and no spouse or partner present. About 30.1% of all households were made up of individuals and 10.2% had someone living alone who was 65 years of age or older. There were 210,184 housing units, of which 6.3% were vacant. Among occupied housing units, 65.7% were owner-occupied and 34.3% were renter-occupied. The homeowner vacancy rate was 1.5% and the rental vacancy rate was 9.4%.[25]

2010 census

As of the 2010 census, there were 430,640 people, 170,197 households, and _ families residing in the county. The population density was 750.5 inhabitants per square mile (289.8/km2). There were 182,262 housing units at an average density of 317.6 per square mile (122.6/km2). The racial makeup of the county was 84.73% White, 6.00% African American, 0.32% Native American, 3.53% Asian, 0.06% Pacific Islander, 2.93% from some other races and 2.42% from two or more races. Hispanic or Latino people of any race were 7.58% of the population.

2000 census

As of the 2000 census, there were 374,601 people, 149,112 households, and 96,624 families residing in the county. The population density was 658.3 inhabitants per square mile (254.2/km2). There were 156,447 housing units at an average density of 275.0 per square mile (106.2/km2). The racial makeup of the county was 88.34% White, 4.84% African American, 0.27% Native American, 2.63% Asian, 0.06% Pacific Islander, 2.22% from some other races and 1.66% from two or more races. Hispanic or Latino people of any race were 4.40% of the population. 25.9% were of German, 10.6% Irish, 9.0% English and 8.4% American ancestry.

Of the 149,112 households 32.20% had children under the age of 18 living with them, 51.00% were married couples living together, 10.30% had a female householder with no husband present, and 35.20% were non-families. 28.10% of households were one person and 8.60% were one person aged 65 or older. The average household size was 2.45 and the average family size was 3.04.

Age spread: 25.70% under the age of 18, 9.40% from 18 to 24, 32.20% from 25 to 44, 21.50% from 45 to 64, and 11.10% 65 or older. The median age was 34 years. For every 100 females, there were 94.20 males. For every 100 females age 18 and over, there were 90.70 males.

The median household income was $46,116 and the median family income was $56,560. Males had a median income of $37,182 versus $28,000 for females. The per capita income for the county was $23,654. About 5.30% of families and 7.90% of the population were below the poverty line, including 9.70% of those under age 18 and 6.40% of those age 65 or over.

Government and infrastructure

The Iowa Department of Corrections Iowa Correctional Institution for Women is in Mitchellville and in Polk County.[28]

United States presidential election results for Polk County, Iowa[29]
Year Republican Democratic Third party(ies)
No.  % No.  % No.  %
1880 4,781 58.50% 2,161 26.44% 1,230 15.05%
1884 6,122 56.06% 4,768 43.66% 30 0.27%
1888 7,049 57.48% 4,966 40.50% 248 2.02%
1892 7,757 53.76% 5,538 38.38% 1,133 7.85%
1896 11,127 60.24% 7,087 38.37% 257 1.39%
1900 12,628 64.72% 6,180 31.67% 703 3.60%
1904 14,113 72.53% 3,086 15.86% 2,259 11.61%
1908 12,555 58.02% 7,924 36.62% 1,161 5.37%
1912 4,665 20.66% 7,239 32.07% 10,671 47.27%
1916 11,295 45.81% 12,327 50.00% 1,034 4.19%
1920 36,073 66.82% 16,281 30.16% 1,632 3.02%
1924 37,491 62.21% 6,665 11.06% 16,114 26.74%
1928 42,290 67.65% 19,725 31.55% 498 0.80%
1932 34,023 49.54% 31,517 45.89% 3,132 4.56%
1936 33,819 42.56% 44,274 55.72% 1,367 1.72%
1940 41,245 44.26% 51,647 55.42% 301 0.32%
1944 36,629 44.07% 46,072 55.43% 417 0.50%
1948 33,742 41.46% 45,289 55.65% 2,348 2.89%
1952 60,934 54.03% 50,867 45.10% 982 0.87%
1956 62,392 54.02% 53,025 45.91% 74 0.06%
1960 64,077 53.74% 55,091 46.20% 66 0.06%
1964 37,280 33.30% 74,194 66.27% 479 0.43%
1968 51,814 45.14% 52,731 45.94% 10,239 8.92%
1972 70,245 52.95% 59,169 44.60% 3,245 2.45%
1976 62,316 45.23% 71,917 52.20% 3,530 2.56%
1980 64,156 44.63% 61,984 43.12% 17,618 12.26%
1984 71,413 48.30% 75,413 51.01% 1,022 0.69%
1988 57,854 40.42% 84,476 59.01% 814 0.57%
1992 63,708 38.09% 78,585 46.98% 24,965 14.93%
1996 60,884 39.00% 83,877 53.73% 11,345 7.27%
2000 79,927 45.89% 89,715 51.51% 4,525 2.60%
2004 95,828 47.29% 105,218 51.93% 1,572 0.78%
2008 89,668 41.82% 120,984 56.43% 3,757 1.75%
2012 96,096 41.98% 128,465 56.13% 4,321 1.89%
2016 93,492 40.38% 119,804 51.74% 18,259 7.89%
2020 106,800 41.27% 146,250 56.52% 5,705 2.20%
2024 112,240 43.70% 140,075 54.54% 4,523 1.76%

Population ranking

The population ranking of the following table is based on the 2020 census of Polk County.

† county seat

Rank City/Town/etc. Municipal type Population
(2020 Census) 		Population
(2024 Estimate)
1 Des Moines † (partially in Warren County) City 214,133 213,096
2 Ankeny City 67,887 76,727
3 West Des Moines (partially in Dallas, Warren and Madison Counties) City 68,723 73,664
4 Urbandale (partially in Dallas County) City 45,580 47,759
5 Johnston City 24,064 25,022
6 Altoona City 19,565 22,598
7 Clive (partially in Dallas County) City 18,601 19,508
8 Grimes (partially in Dallas County) City 15,392 17,266
9 Norwalk (mostly in Warren County) City 12,799 15,396
10 Pleasant Hill City 10,147 11,942
11 Bondurant City 7,365 9,511
12 Polk City City 5,543 6,430
13 Windsor Heights City 5,252 5,106
14 Carlisle (partially in Warren County) City 4,160 4,381
15 Saylorville CDP 3,584 3,559
16 Mitchellville (partially in Jasper County) City 2,485 2,686
17 Granger (mostly in Dallas County) City 1,654 2,095
18 Elkhart City 882 1,079
19 Runnells City 457 467
20 Alleman City 423 439
21 Sheldahl (partially in Boone and Story Counties) City 297 312

Education

School districts include:[30]

Attractions

Communities

Cities

Census-designated place

Unincorporated communities

Townships

See also

References

  1. ^ "Iowa County Names and Numbers". Iowa Department of Administrative Services. Retrieved February 17, 2026.
  2. ^ "Explore Census Data". United States Census Bureau. Retrieved February 17, 2026.
  3. ^ a b c "U.S. Census Bureau QuickFacts: Polk County, Iowa". www.census.gov. Retrieved February 17, 2026.
  4. ^ "Find a County". National Association of Counties. Retrieved February 17, 2026.
  5. ^ "Iowa: Individual County Chronologies". publications.newberry.org. The Newberry Library. 2007. Retrieved February 17, 2026.
  6. ^ The counties were Boone, Clarke, Dallas, Decatur, Jasper, Lucas, Madison, Marshall, Polk, Story, Warren, and Wayne.
  7. ^ The history of Polk County, Iowa: containing a history of the county, its cities, towns, &c. Union Historical Co. 1880. Retrieved February 27, 2025.
  8. ^ The history of Polk County, Iowa : containing a history of the county, its cities, towns, &c. Union Historical Co. 1880. pp. 419, 425. Retrieved February 27, 2025.
  9. ^ Polk County
  10. ^ "2025 County Gazetteer Files – Iowa". United States Census Bureau. Retrieved February 17, 2026.
  11. ^ "U.S. Census Bureau QuickFacts: Polk County, Iowa". www.census.gov. Retrieved February 17, 2026.
  12. ^ "County Population Totals and Components of Change: 2020-2024". Retrieved July 24, 2025.
  13. ^ "U.S. Decennial Census". United States Census Bureau. Retrieved January 7, 2014.
  14. ^ "Historical Census Browser". University of Virginia Library. 2007. Archived from the original on December 12, 2009. Retrieved January 7, 2014.
  15. ^ Forstall, Richard L. (April 20, 1995). "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau. Archived from the original on February 19, 1999. Retrieved January 7, 2014.
  16. ^ "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000" (PDF). United States Census Bureau. Archived (PDF) from the original on March 27, 2010. Retrieved January 7, 2014.
  17. ^ "County Median Home Price". National Association of Realtors. Retrieved February 17, 2026.
  18. ^ "Polk County, Iowa — Population by Race". CensusScope. Retrieved February 17, 2026.
  19. ^ "1990 Census of Population: General Population Characteristics Iowa" (PDF). www.census.gov. October 6, 2022. p. 30. Retrieved February 17, 2026.
  20. ^ "P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – Polk County, Iowa". United States Census Bureau. Retrieved February 17, 2026.
  21. ^ "P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2010: DEC Redistricting Data (PL 94-171) – Polk County, Iowa". United States Census Bureau. Retrieved February 17, 2026.
  22. ^ "P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2020: DEC Redistricting Data (PL 94-171) – Polk County, Iowa". United States Census Bureau. Retrieved February 17, 2026.
  23. ^ "U.S. Census Bureau, Table P16: Household Type". United States Census Bureau. Retrieved February 17, 2026.
  24. ^ "How many people live in Polk County, Iowa". USA Today. Retrieved February 17, 2026.
  25. ^ a b "2020 Decennial Census Demographic Profile (DP1)". United States Census Bureau. 2021. Retrieved December 25, 2025.
  26. ^ "2020 Decennial Census Redistricting Data (Public Law 94-171)". United States Census Bureau. 2021. Retrieved December 25, 2025.
  27. ^ "2020 Decennial Census Demographic and Housing Characteristics (DHC)". United States Census Bureau. 2023. Retrieved December 25, 2025.
  28. ^ "Iowa Correctional Institution for Women". Iowa Department of Corrections. Retrieved February 17, 2026.
  29. ^ Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections". uselectionatlas.org. Retrieved December 8, 2020.
  30. ^ 2020 Census - School District Reference Map: Polk County, IA (PDF) (Map). United States Census Bureau. January 15, 2021. Retrieved February 17, 2026. - Text list
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