Woodbury County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 105,941, and was estimated to be 106,649 in 2025, making it the seventh-most populous county in Iowa. The county seat and the largest city is Sioux City.
Woodbury County is included in the Sioux City metropolitan area.
Originally established in 1851 as Wahkaw County, the Iowa Legislature in 1853 changed the name to Woodbury County in honor of Levi Woodbury (1789âÂÂ1851), a senator and governor of New Hampshire who served as a Supreme Court justice from 1844 until his death.
The first county seat of Wahkaw County was the now-extinct village of Thompsonville; when the Legislature changed the county name to Woodbury, the new county seat became Sergeant's Bluff (now Sergeant Bluff). The county seat was moved to Sioux City in 1856.
The Winnebago Tribe of Nebraska (Ho-Chunk) owns reservation land in Woodbury County.
The county is on the western edge of Iowa, with its western border being the Missouri River.
According to the United States Census Bureau, the county has a total area of , of which is land and (0.56%) is water. It is the third-largest county in Iowa by total area.
As of the third quarter of 2025, the median home value in Woodbury County was $201,273.
As of the 2024 American Community Survey, there are 40,764 estimated households in Woodbury County with an average of 2.56 persons per household. The county has a median household income of $78,923. Approximately 13.7% of the county's population lives at or below the poverty line. Woodbury County has an estimated 66.0% employment rate, with 27.5% of the population holding a bachelor's degree or higher and 87.8% holding a high school diploma. There were 43,701 housing units at an average density of .
The median age in the county was 35.2 years.
As of the 2024 estimate, there were 107,257 people, 40,764 households, and _ families residing in the county. The population density was . There were 43,701 housing units at an average density of . The racial makeup of the county was 83.3% White (65.8% NH White), 6.1% African American, 3.3% Native American, 3.1% Asian, 1.0% Pacific Islander, _% from some other races and 3.1% from two or more races. Hispanic or Latino people of any race were 20.5% of the population.
As of the 2020 census, there were 105,941 people, 39,904 households, and 25,784 families residing in the county. The population density was . There were 42,701 housing units at an average density of . The racial makeup of the county was 72.49% White, 4.91% African American, 2.37% Native American, 2.84% Asian, 0.62% Pacific Islander, 7.70% from some other races and 9.07% from two or more races. Hispanic or Latino people of any race were % of the population.
The median age was 35.8 years; 26.0% of residents were under the age of 18 and 15.4% of residents were 65 years of age or older. For every 100 females there were 99.2 males, and for every 100 females age 18 and over there were 97.5 males age 18 and over.
83.9% of residents lived in urban areas, while 16.1% lived in rural areas.
There were 39,904 households, of which 32.9% had children under the age of 18 living in them. Of all households, 44.7% were married-couple households, 20.2% were households with a male householder and no spouse or partner present, and 26.9% were households with a female householder and no spouse or partner present. About 28.8% of all households were made up of individuals and 11.9% had someone living alone who was 65 years of age or older.
Among the 42,701 housing units, 6.6% were vacant. Of the occupied units, 64.9% were owner-occupied and 35.1% were renter-occupied. The homeowner vacancy rate was 1.3% and the rental vacancy rate was 7.6%.
As of the 2010 census, there were 102,172 people, 39,052 households, and _ families residing in the county. The population density was . There were 41,484 housing units at an average density of . The racial makeup of the county was 83.57% White, 2.40% African American, 2.21% Native American, 2.37% Asian, 0.10% Pacific Islander, 6.11% from some other races and 3.24% from two or more races. Hispanic or Latino people of any race were % of the population.
As of the 2000 census, there were 103,877 people, 39,151 households, and 26,426 families residing in the county. The population density was . There were 41,394 housing units at an average density of . The racial makeup of the county was 87.48% White, 2.02% African American, 1.69% Native American, 2.41% Asian, 0.04% Pacific Islander, 4.37% from some other races and 1.99% from two or more races. Hispanic or Latino people of any race were 9.11% of the population.
There were 39,151 households, 34.00% had children under the age of 18 living with them, 51.90% were married couples living together, 11.30% had a female householder with no husband present, and 32.50% were non-families. 26.60% of households were one person and 11.20% were one person aged 65 or older. The average household size was 2.58 and the average family size was 3.13.
The age distribution was 27.30% under the age of 18, 10.20% from 18 to 24, 28.30% from 25 to 44, 20.80% from 45 to 64, and 13.40% 65 or older. The median age was 34 years. For every 100 females, there were 96.10 males. For every 100 females age 18 and over, there were 92.80 males.
The median household income was $38,509 and the median family income was $46,499. Males had a median income of $31,664 versus $22,599 for females. The per capita income for the county was $18,771. About 7.20% of families and 10.30% of the population were below the poverty line, including 13.60% of those under age 18 and 7.40% of those age 65 or over.
For much of the second half of the 20th century, Woodbury County tilted Republican, albeit not as overwhelmingly as most of western Iowa. Between 1988 and 2012 Woodbury County was the quintessential swing county in Iowa. No candidate won it by more than 3.5% over that quarter-century. This was the only county in Iowa that Barack Obama won in 2012 that he failed to carry in 2008. However, in 2016, Woodbury County, like Iowa as a whole, swung over dramatically to Donald Trump, who carried it by a 19 percent margin, the largest margin of victory since Lyndon Johnson's landslide election in 1964.
The population ranking of the following table is based on the 2020 census of Woodbury County.
â county seat
School districts include:
Former school districts include: