Deuel County lies on the east boundary line of South Dakota. Its east boundary line abuts the west boundary line of the state of Minnesota. Its terrain consists of rolling hills, sloped to the northeast. The area is largely devoted to agriculture. The county's highest elevation occurs on its upper west boundary line, at 1,936 ft (590 m) ASL.[6] The county has a total area of 637 square miles (1,650 km2), of which 623 square miles (1,610 km2) is land and 14 square miles (36 km2) (2.2%) is water.[7]
U.S. Decennial Census[26] 1790-1960[27] 1900-1990[28] 1990-2000[29] 2010-2020[2]
2020 census
As of the 2020 census, there were 4,295 people, 1,786 households, and 1,177 families residing in the county.[30] The population density was 6.9 inhabitants per square mile (2.7/km2). There were 2,132 housing units.
2010 census
As of the 2010 census, there were 4,364 people, 1,819 households, and 1,228 families in the county. The population density was 7.0 inhabitants per square mile (2.7/km2). There were 2,204 housing units at an average density of 3.5 units per square mile (1.4 units/km2). The racial makeup of the county was 97.5% white, 0.3% American Indian, 0.3% black or African American, 0.1% Asian, 1.0% from other races, and 0.9% from two or more races. Those of Hispanic or Latino origin made up 2.0% of the population. In terms of ancestry, 50.4% were German, 25.4% were Norwegian, 8.0% were Irish, 6.6% were Dutch, 5.5% were English, and 2.9% were American.
Of the 1,819 households, 28.2% had children under the age of 18 living with them, 58.6% were married couples living together, 5.0% had a female householder with no husband present, 32.5% were non-families, and 29.1% of all households were made up of individuals. The average household size was 2.37 and the average family size was 2.92. The median age was 43.9 years.
The median income for a household in the county was $47,000 and the median income for a family was $55,439. Males had a median income of $35,197 versus $26,020 for females. The per capita income for the county was $22,276. About 3.0% of families and 6.1% of the population were below the poverty line, including 5.6% of those under age 18 and 11.9% of those age 65 or over.
Deuel County is a typical eastern South Dakota county in its political history, which is somewhat akin to the Midwestern states of Iowa and Minnesota. It was strongly Republican in its early years, with no Democrat except William Jennings Bryan gaining forty percent up to 1928. Franklin D. Roosevelt in 1932 became the first Democrat to carry the county, but lost it to Alf Landon in 1936, whilst – like most of the Midwest – the county showed a powerful anti-Roosevelt trend in 1940 and 1944 due to opposition to World War II. From 1964, the county showed a strong trend towards the Democratic Party – so much so that it was one of only 130 counties nationwide to support South Dakota native George McGovern in 1972 against Richard Nixon, and one of only five nationwide to have supported both landslide losers Landon and McGovern.[a]
Between 1976 and 2010, Deuel was a competitive swing county, voting for the winning candidate in every election until 2008 when Barack Obama lost by 34 votes. Over the past three elections, however, Deuel – in common with many rural counties nationwide – has shown an abrupt swing towards the Republican Party. Donald Trump’s 2016 win was the largest since Dwight D. Eisenhower in 1952.
United States presidential election results for Deuel County, South Dakota[32]