Plymouth County

History

Plymouth County was formed on January 15, 1851. Settlement began in the county in 1856. In October 1859, the first courthouse was built in Melbourne, formerly located in the southeast quarter of section 34, Plymouth Township, about five to six miles due south of Merrill. The first public school opened its doors there with 32 pupils. In 1872 the county seat was moved to Le Mars and a courthouse and jail were built there in 1873. The present Plymouth County Courthouse was built in 1900 of red sandstone.

During the Great Depression, farmers in the county organized the Farmers Holiday Group, to keep farm products off the market until the desired price was met. A radical group among them abducted Judge Bradley from his court chamber and threatened to hang him in the front of the courthouse. Bradley was freed, but the governor ordered the national guard to Plymouth County and declared a state of emergency, which effectively ended the group.

Geography

According to the United States Census Bureau, the county has a total area of 863.668 square miles (2,236.89 km2), of which 862.828 square miles (2,234.71 km2) is land and 0.840 square miles (2.18 km2) (0.10%) is water. It is the fourth-largest county in Iowa by total area.

Adjacent counties

Sioux County (north)

Cherokee County (east)

Woodbury County (south)

Union County, South Dakota (west)

Transportation

Major highways

U.S. Highway 75

Iowa Highway 3

Iowa Highway 12

Iowa Highway 60

Iowa Highway 140

Airport

Le Mars Municipal Airport is located in Plymouth County, two nautical miles (3.7 km) southwest of the central business district of Le Mars.

Demographics

As of the second quarter of 2025, the median home value in Plymouth County was $245,947.

As of the 2024 American Community Survey, there are 10,313 estimated households in Plymouth County with an average of 2.46 persons per household. The county has a median household income of $83,251. Approximately 6.9% of the county's population lives at or below the poverty line. Plymouth County has an estimated 67.1% employment rate, with 21.7% of the population holding a bachelor's degree or higher and 94.8% holding a high school diploma. There were 10,891 housing units at an average density of 12.62 per square mile (4.9/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 (93.1%), Spanish (4.3%), Indo-European (0.5%), Asian and Pacific Islander (0.7%), and Other (1.5%).

The median age in the county was 41.3 years.

2024 estimate

As of the 2024 estimate, there were 25,825 people, 10,313 households, and _ families residing in the county. The population density was 11.95 inhabitants per square mile (4.6/km2). There were 10,891 housing units at an average density of 12.62 per square mile (4.9/km2). The racial makeup of the county was 93.2% White (87.1% NH White), 2.6% African American, 1.0% Native American, 0.7% Asian, 1.0% Pacific Islander, _% from some other races and 1.5% from two or more races. Hispanic or Latino people of any race were 7.1% of the population.

2020 census

As of the 2020 census, there were 25,698 people, 10,171 households, and 7,048 families residing in the county. The population density was 29.78 inhabitants per square mile (11.5/km2). There were 10,818 housing units at an average density of 12.54 per square mile (4.8/km2). The racial makeup of the county was 90.63% White, 1.39% African American, 0.34% Native American, 0.45% Asian, 0.46% Pacific Islander, 2.55% from some other races and 4.19% from two or more races. Hispanic or Latino people of any race were 5.82% of the population.

The median age was 40.6 years; 25.2% of residents were under the age of 18 and 19.1% of residents were 65 years of age or older. For every 100 females there were 100.5 males, and for every 100 females aged 18 and over there were 98.4 males age 18 and over.

39.5% of residents lived in urban areas, while 60.5% lived in rural areas.

There were 10,171 households in the county, of which 30.6% had children under the age of 18 living in them. Of all households, 56.4% were married-couple households, 17.4% were households with a male householder and no spouse or partner present, and 20.3% were households with a female householder and no spouse or partner present. About 26.3% of all households were made up of individuals and 12.7% had someone living alone who was 65 years of age or older.

There were 10,818 housing units, of which 6.0% were vacant. Among occupied housing units, 77.0% were owner-occupied and 23.0% were renter-occupied. The homeowner vacancy rate was 0.8% and the rental vacancy rate was 6.8%.

2010 census

As of the 2010 census, there were 24,986 people, 10,171 households, and _ families residing in the county. The population density was 28.96 inhabitants per square mile (11.2/km2). There were 10,550 housing units at an average density of 12.23 per square mile (4.7/km2). The racial makeup of the county was 96.39% White, 0.30% African American, 0.28% Native American, 0.47% Asian, 0.06% Pacific Islander, 1.48% from some other races and 1.00% from two or more races. Hispanic or Latino people of any race were 2.97% of the population.

2000 census

As of the 2000 census, there were 24,849 people, 9,372 households, and 6,804 families residing in the county. The population density was 28.80 inhabitants per square mile (11.1/km2). There were 9,880 housing units at an average density of 11.45 per square mile (4.4/km2). The racial makeup of the county was 98.16% White, 0.29% African American, 0.14% Native American, 0.27% Asian, 0.06% Pacific Islander, 0.46% from some other races and 0.62% from two or more races. Hispanic or Latino people of any race were 1.32% of the population.

There were 9,372 households 35.70% had children under the age of 18 living with them, 63.30% were married couples living together, 6.20% had a female householder with no husband present, and 27.40% were non-families. 24.00% of households were one person and 12.00% were one person aged 65 or older. The average household size was 2.61 and the average family size was 3.12.

The age distribution was 28.30% under the age of 18, 7.20% from 18 to 24, 26.40% from 25 to 44, 22.00% from 45 to 64, and 16.00% 65 or older. The median age was 38 years. For every 100 females there were 98.80 males. For every 100 females age 18 and over, there were 95.70 males.

The median household income was $41,638 and the median family income was $50,009. Males had a median income of $33,566 versus $22,558 for females. The per capita income for the county was $19,442. About 4.40% of families and 6.00% of the population were below the poverty line, including 6.70% of those under age 18 and 6.40% of those age 65 or over.

Points of interest

The Pappas Telecasting Tower, with a height of 603.5 metres (1,980 ft), is one of the tallest masts in the world.

Notable people

William G. Kirchner, Minnesota state legislator and banker

Ralph Klemme, Iowa state legislator and farmer

Jim Nicholson, Former Secretary of Veterans Affairs, Republican National Chairman and U.S. Ambassador to the Vatican

Johnny Niggeling, Major league baseball pitcher

Paul Rust, actor and comedian

Thomas Starzl, innovator in organ transplant surgery

Isaac S. Struble, Congressman (1883–1891) after whom Struble is named

William Garner Waddel, South Dakota State Senator

Communities

Population ranking

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

† county seat

Politics

Like most of Northwest Iowa, Plymouth County is a Republican Party stronghold. Lyndon B. Johnson is the last Democrat to win the county in a presidential election, and in elections from 1896 on it has only been won by a Democrat nationally four other times.

Education

School districts include:

Akron–Westfield Community School District, Akron

Hinton Community School District, Hinton

Kingsley–Pierson Community School District, Kingsley

Lawton–Bronson Community School District, Lawton

Le Mars Community School District, Le Mars

Marcus-Meriden-Cleghorn Community School District, Marcus

Remsen Union Community School District, Remsen

Sioux City Community School District, Sioux City

West Sioux Community School District, Hawarden