Union County, South Dakota

Union County
County
Chicago and North Western Railway depot in Beresford, South Dakota
Location within the U.S. state of South Dakota
South Dakota's location within the U.S.
Coordinates: 42°50′N 96°39′W / 42.83°N 96.65°W / 42.83; -96.65
Country	United States
State	South Dakota
Founded	April 10, 1862
Seat	Elk Point
Largest community	Dakota Dunes
Area
• Total	467 sq mi (1,210 km2)
• Land	461 sq mi (1,190 km2)
• Water	6.6 sq mi (17 km2)  1.4%
Population  (2020)
• Total	16,811
• Estimate  (2023)	17,183
• Density	36/sq mi (14/km2)
Time zone	UTC−6 (Central)
• Summer (DST)	UTC−5 (CDT)
Congressional district	At-large
Website	unioncountysd.org

Union County is the southernmost county in the U.S. state of South Dakota. As of the 2020 census, the population was 16,811,^[1] making it the 13th most populous county in South Dakota. Its county seat has been Elk Point since April 30, 1865.^[2] Originally named Cole County, its name was changed to Union on January 7, 1864, because of Civil War sentiment.

Union County is part of the Sioux City, IA–NE–SD Metropolitan Statistical Area. The Progressive Farmer rated Union County second in the "2006 Best Place to Live Survey" in the U.S., because "its schools are good, its towns neat and its people friendly".