Polk County, Iowa

History

On January 13, 1846, the legislative body of the Iowa Territory authorized the creation of twelve counties in the Territory, 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. 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.

Geography

According to the United States Census Bureau, the county has a total area of 591.888 sqmi, of which 572.720 sqmi is land and 19.168 sqmi (3.0%) is water. The county is bisected by the Des Moines River.

Major highways

• [[File:I-35.svg|x20px]] Interstate 35
• [[File:I-80.svg|x20px]] Interstate 80
• [[File:I-235.svg|x20px]] Interstate 235
• [[File:US 6.svg|x20px]] U.S. Highway 6
• [[File:US 65.svg|x20px]] U.S. Highway 65
• [[File:US 69.svg|x20px]] U.S Route 69
• [[File:Circle sign 5.svg|x20px]] Iowa Highway 5
• [[File:Elongated circle 17.svg|x20px]] Iowa Highway 17
• [[File:Elongated circle 28.svg|x20px]] Iowa Highway 28
• [[File:Elongated circle 141.svg|x20px]] Iowa Highway 141
• [[File:Elongated circle 160.svg|x20px]] Iowa Highway 160
• [[File:Elongated circle 163.svg|x20px]] Iowa Highway 163
• [[File:Elongated circle 210.svg|x20px]] Iowa Highway 210
• [[File:Elongated circle 415.svg|x20px]] Iowa Highway 415

Transit

• Des Moines Area Regional Transit
• Burlington Trailways
• Jefferson Lines
• Des Moines Bus Station

Demographics

|align-fn=center 1790–1960 1900–1990 1990–2000 2010–2020

As of the third quarter of 2024, the median home value in Polk County was $285,410.

As of the 2023 American Community Survey, there are 202,404 estimated households in Polk County with an average of 2.41 persons per household. The county has a median household income of $81,621. Approximately 11.5% of the county's population lives at or below the poverty line. Polk County has an estimated 71.0% employment rate, with 39.5% of the population holding a bachelor's degree or higher and 83.7% holding a high school diploma.

The top five reported ancestries (people were allowed to report up to two ancestries, thus the figures will generally add to more than 100%) were English (85.2%), Spanish (7.8%), Indo-European (1.5%), Asian and Pacific Islander (3.2%), and Other (2.2%).

The median age in the county was 36.8 years.

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.

2020 census

As of the 2020 census, there were 492,401 people, 196,891 households, and 121,993 families residing in the county. The population density was 860.5 PD/sqmi. There were 210,184 housing units at an average density of 367.3 /sqmi.

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.

The racial makeup of the county was 75.9% White, 7.2% Black or African American, 0.5% American Indian and Alaska Native, 5.0% Asian, 0.1% Native Hawaiian and Pacific Islander, 3.9% from some other race, and 7.5% from two or more races. Hispanic or Latino residents of any race comprised 9.8% of the population.

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

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%.

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 PD/sqmi. There were 182,262 housing units at an average density of 317.6 /sqmi. 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 PD/sqmi. There were 156,447 housing units at an average density of 275.0 /sqmi. 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.

Population ranking

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

† county seat

Education

School districts include:

• Ankeny Community School District
• Ballard Community School District
• Bondurant-Farrar Community School District
• Carlisle Community School District
• Collins-Maxwell Community School District
• Dallas Center-Grimes Community School District
• Des Moines Independent Community School District
• Johnston Community School District
• Madrid Community School District
• North Polk Community School District
• PCM Community School District
• Saydel Community School District
• Southeast Polk Community School District
• Urbandale Community School District
• West Des Moines Community School District
• Woodward-Granger Community School District

Attractions

• Adventureland Resort
• Blank Park Zoo
• Casey's Center
• Iowa State Capitol
• Iowa State Fair
• Living History Farms
• Science Center of Iowa
• Valley Junction

Communities

Cities

• Alleman
• Altoona
• Ankeny
• Bondurant
• Carlisle
• Clive
• Des Moines
• Elkhart
• Granger
• Grimes
• Johnston
• Mitchellville
• Norwalk
• Pleasant Hill
• Polk City
• Runnells
• Sheldahl
• Urbandale
• West Des Moines
• Windsor Heights

Census-designated place

• Saylorville

Unincorporated communities

• Adelphi
• Andrews
• Avon
• Avon Lake
• Berwick
• Capitol Heights
• Crocker
• Enterprise
• Farrar
• Herrold
• Ivy
• Lovington
• Norwoodville
• Oralabor
• Polk City Junction
• Rising Sun
• Santiago
• Saylor
• Swanwood
• White Oak
• Zook Spur

Townships

• Allen
• Beaver
• Bloomfield
• Camp
• Clay
• Crocker
• Delaware
• Des Moines
• Douglas
• Elkhart
• Four Mile
• Franklin
• Jefferson
• Lee
• Lincoln
• Madison
• Saylor
• Union
• Walnut
• Washington
• Webster

References

References

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4. The counties were Boone, Clarke, Dallas, Decatur, Jasper, Lucas, Madison, Marshall, Polk, Story, Warren, and Wayne.
5. (1880). "The history of Polk County, Iowa: containing a history of the county, its cities, towns, &c.". Union Historical Co..
6. (1880). "The history of Polk County, Iowa : containing a history of the county, its cities, towns, &c.". Union Historical Co..
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14. "County Median Home Price". [[National Association of Realtors]].
15. "U.S. Census Bureau QuickFacts: Polk County, Iowa".
16. "Polk County, Iowa — Population by Race". CensusScope.
17. "Polk County, Iowa — Population by Race". CensusScope.
18. "P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – Polk County, Iowa". [[United States Census Bureau]].
19. "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]].
20. "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]].
21. (2021). "2020 Decennial Census Demographic Profile (DP1)".
22. (2021). "2020 Decennial Census Redistricting Data (Public Law 94-171)".
23. (2023). "2020 Decennial Census Demographic and Housing Characteristics (DHC)".
24. link. (July 22, 2011. [[Iowa Department of Corrections]]. Retrieved November 29, 2010.)
25. Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections".
26. "2020 CENSUS - SCHOOL DISTRICT REFERENCE MAP: Polk County, IA". [[United States Census Bureau]].