Brown County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 38,301, making it the fourth most populous county in South Dakota. Its county seat is Aberdeen. The county is named for Alfred Brown, of Hutchinson County, South Dakota, a Dakota Territory legislator in 1879. Brown County is part of the Aberdeen, SD Micropolitan Statistical Area.

Geography

Brown County lies on the north side of South Dakota. Its north boundary line abuts the south boundary line of the state of North Dakota. The James River flows south-southwest through the county; its entry point into neighboring Spink County marks Brown County's lowest elevation: 1,266 ft ASL. The terrain of Brown County consists of rolling terrain, sloping to the south and east, largely devoted to agriculture. The county has a total area of 1731 sqmi, of which 1713 sqmi is land and 18 sqmi (1.0%) is water.

Major highways

Adjacent counties

Protected areas

Demographics

2020 census

As of the 2020 census, there were 38,301 people, 16,130 households, and 9,595 families residing in the county. The population density was 22.4 PD/sqmi. There were 17,885 housing units.

2010 census

As of the 2010 census, there were 36,531 people, 15,489 households, and 9,374 families in the county. The population density was 21.3 PD/sqmi. There were 16,706 housing units at an average density of 9.8 /sqmi. The racial makeup of the county was 93.2% white, 3.0% American Indian, 1.0% Asian, 0.5% black or African American, 0.1% Pacific islander, 0.4% from other races, and 1.7% from two or more races. Those of Hispanic or Latino origin made up 1.4% of the population. In terms of ancestry. Of the 15,489 households, 28.4% had children under the age of 18 living with them, 48.5% were married couples living together, 8.1% had a female householder with no husband present, 39.5% were non-families, and 33.0% of all households were made up of individuals. The average household size was 2.27 and the average family size was 2.89. The median age was 38.6 years. The median income for a household in the county was $45,615 and the median income for a family was $58,683. Males had a median income of $37,997 versus $28,419 for females. The per capita income for the county was $23,878. About 5.6% of families and 10.2% of the population were below the poverty line, including 9.6% of those under age 18 and 15.4% of those age 65 or over.

Politics

Brown County was long a Democratic stronghold, home to notable Democrats including South Dakota Governor Ralph Herseth, US Senate majority leader Tom Daschle and Congresswoman Stephanie Herseth Sandlin. It generally voted Democratic except in Republican landslides (though often relatively narrowly margins) in presidential elections from 1932 until 1996. Since then, Brown County has trended Republican, particularly at the local level, although the county was carried by Barack Obama in 2008.

Communities

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Unincorporated communities

Townships