Des Moines County sits on Iowa's eastern border alongside theMississippi River. The city of Des Moines is inPolk County in central Iowa. Both places derive their name from theDes Moines River, which flows through the city of Des Moines and originally flowed through the county. When the county was divided early in Iowa's history, the river ended up further west, forming the border between Lee County, Iowa and the state of Missouri.
At an extra session of the Sixth Legislative Assembly ofMichigan Territory held in September 1834, theIowa District was divided into two counties by running a line due west from the lower end ofRock Island in theMississippi River. The territory north of this line (which started just south of the present-dayDavenport) was named Dubuque County, and all south of it was Demoine County. It was named after theDes Moines River. From July 3, 1836, until July 3, 1838, Des Moines County was part ofWisconsin Territory. The county underwent various border changes during this time. July 4, 1838, the named county became part ofIowa Territory (later the state of Iowa).[5][6][7]
According to theUnited States Census Bureau, the county has a total area of 429.775 square miles (1,113.11 km2), of which 416.129 square miles (1,077.77 km2) is land and 13.646 square miles (35.34 km2) (3.18%) is water.[9] It is the 93rd largest county in Iowa by total area.[10]
The Mississippi River forms the east border;Skunk River, the south border; and the county is drained byFlint Creek.[11]
As of the second quarter of 2025, the median home value in Des Moines County was $154,139.[17]
As of the 2023American Community Survey, there are 17,188 estimated households in Des Moines County with an average of 2.21 persons per household. The county has a median household income of $60,662. Approximately 14.1% of the county's population lives at or below thepoverty line. Des Moines County has an estimated 59.3% employment rate, with 23.8% of the population holding a bachelor's degree or higher and 94.0% holding a high school diploma.[3] There were 18,778 housing units at an average density of 45.13 per square mile (17.4/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 (96.3%), Spanish (2.2%), Indo-European (0.5%), Asian and Pacific Islander (0.9%), and Other (0.1%).
The median age in the county was 42.2 years.
Des Moines 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.
As of the 2024 estimate, there were 38,411 people, 17,188 households, and _ families residing in the county. The population density was 92.31 inhabitants per square mile (35.6/km2). There were 18,778 housing units at an average density of 45.13 per square mile (17.4/km2). The racial makeup of the county was 87.9% White(84.7% NH White), 6.6% African American, 0.4% Native American, 1.8% Asian, 0.1% Pacific Islander, _% from some other races and 3.3% from two or more races. Hispanic or Latino people of any race were 4.1% of the population.
Population of Des Moines County from the U.S. census data
As of the2020 census, there were 38,910 people, 16,751 households, and 10,297 families residing in the county.[23] Thepopulation density was 93.50 inhabitants per square mile (36.1/km2). There were 18,782 housing units at an average density of 45.14 per square mile (17.4/km2). The racial makeup of the county was 85.23%White, 6.51%African American, 0.20%Native American, 1.04%Asian, 0.06%Pacific Islander, 1.22% from some other races and 5.74% from two or more races.Hispanic or Latino people of any race were 3.20% of the population.[24][25][26]
The median age was 42.9 years. 21.8% of residents were under the age of 18 and 21.7% of residents were 65 years of age or older. For every 100 females there were 96.3 males, and for every 100 females age 18 and over there were 94.3 males age 18 and over.
There were 16,751 households in the county, of which 26.3% had children under the age of 18 living in them. Of all households, 43.9% were married-couple households, 20.0% were households with a male householder and no spouse or partner present, and 28.4% were households with a female householder and no spouse or partner present. About 32.6% of all households were made up of individuals and 15.4% had someone living alone who was 65 years of age or older.
There were 18,782 housing units, of which 10.8% were vacant. Among occupied housing units, 70.7% were owner-occupied and 29.3% were renter-occupied. The homeowner vacancy rate was 3.0% and the rental vacancy rate was 11.0%.
73.0% of residents lived in urban areas, while 27.0% lived in rural areas.
As of the2010 census, there were 40,325 people, 17,003 households, and _ families residing in the county. The population density was 96.91 inhabitants per square mile (37.4/km2). There were 18,535 housing units at an average density of 44.54 per square mile (17.2/km2). The racial makeup of the county was 91.02%White, 5.08%African American, 0.25%Native American, 0.72%Asian, 0.05%Pacific Islander, 0.58% from some other races and 2.31% from two or more races.Hispanic or Latino people of any race were 2.58% of the population.
As of the2000 census, there were 42,351 people, 17,270 households, and 11,536 families residing in the county. The population density was 102.0 inhabitants per square mile (39.4/km2). There were 18,643 housing units at an average density of 45.0 per square mile (17.4/km2). The racial makeup of the county was 93.69%White, 3.57%African American, 0.25%Native American, 0.59%Asian, 0.05%Pacific Islander, 0.68% from some other races and 1.18% from two or more races.Hispanic or Latino people of any race were 1.75% of the population.
There were 17,270 households, out of which 29.60% had children under the age of 18 living with them, 52.70% weremarried couples living together, 10.50% had a female householder with no husband present, and 33.20% were non-families. 28.60% of all households were made up of individuals, and 12.60% had someone living alone who was 65 years of age or older. The average household size was 2.40 and the average family size was 2.94.
In the county, the population was spread out, with 24.40% under the age of 18, 8.50% from 18 to 24, 26.10% from 25 to 44, 24.30% from 45 to 64, and 16.70% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 93.50 males. For every 100 females age 18 and over, there were 90.30 males.
The median income for a household in the county was $36,790, and the median income for a family was $45,089. Males had a median income of $34,880 versus $22,530 for females. Theper capita income for the county was $19,701. About 8.20% of families and 10.70% of the population were below thepoverty line, including 17.30% of those under age 18 and 7.40% of those age 65 or over.
From1896 through1960, Des Moines County was a primarily Republican county, backing Democratic nominees only four times in the period (Woodrow Wilson in1912, with a low plurality;Franklin Roosevelt in his two landslides in1932 and1936; andHarry Truman in1948). From1964 through2012, it became a Democratic stronghold, backing the Democratic nominee in every election in this period save inNixon's1972 landslide. In2016,Donald Trump became the first Republican since 1972 to carry the county, despite narrowly losing the overall national popular vote; the county swung over 25% in his favor relative to its2012 vote.[27] The change to the GOP happened while the county experienced an economic decline.[28] In2020 and2024, Trump again carried the county, with an increased vote share each time, the first time the county has voted Republican three times in a row since between 1952 and 1960.
United States presidential election results for Des Moines County, Iowa[29]