Walworth County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 5,315. Its county seat is Selby. The county was created in 1873 and organized in 1883. It is named for Walworth County, Wisconsin. flows southward along the county's west boundary line. Swan Creek flows west-northwest through the county's SW corner, discharging into the Missouri. The county's terrain consists of semi-arid rolling hills, carved by drainages and gullies. Most of the area is devoted to agriculture. The terrain slopes to the south and east, although the western portion of the county drops westward into the Missouri River valley. The county's highest point is on the eastern portion of its north boundary line, at 1,982 ft ASL. The county has a total area of 745 sqmi, of which 709 sqmi is land and 36 sqmi (4.8%) is water. The eastern portion of South Dakota's counties (48 of 66) observe Central Time; the western counties (18 of 66) observe Mountain Time. Walworth County is the westernmost of the SD counties to observe Central Time.

Major highways

Adjacent counties

Protected areas

Lakes

Demographics

2020 census

As of the 2020 census, there were 5,315 people, 2,271 households, and 1,400 families in the county. The population density was 7.5 PD/sqmi. There were 2,927 housing units.

2010 census

As of the 2010 census, there were 5,438 people, 2,392 households, and 1,490 families in the county. The population density was 7.7 PD/sqmi. There were 3,003 housing units at an average density of 4.2 /mi2. The racial makeup of the county was 82.6% white, 14.3% American Indian, 0.2% Asian, 0.1% black or African American, 0.2% from other races, and 2.6% from two or more races. Those of Hispanic or Latino origin made up 0.7% of the population. In terms of ancestry, 56.9% were German, 12.5% were Norwegian, 8.9% were Russian, 5.4% were Irish, and 3.1% were American. Of the 2,392 households, 25.9% had children under the age of 18 living with them, 49.2% were married couples living together, 8.9% had a female householder with no husband present, 37.7% were non-families, and 32.8% of all households were made up of individuals. The average household size was 2.21 and the average family size was 2.79. The median age was 47.2 years. The median income for a household in the county was $39,517 and the median income for a family was $51,250. Males had a median income of $37,857 versus $21,551 for females. The per capita income for the county was $23,716. About 7.5% of families and 14.5% of the population were below the poverty line, including 23.6% of those under age 18 and 14.4% of those age 65 or over.

Communities

Cities

Towns

Unincorporated community

Unorganized territory

Politics

Walworth County voters have been reliably Republican for decades. Only three Democratic presidential candidates have ever carried the county: William Jennings Bryan in 1896, Franklin D. Roosevelt in 1932 and 1936, and Lyndon Johnson in 1964.