Union County, South Dakota

Founded on April 10, 1862, as Cole County, it was renamed Union County on January 7, 1864, when its boundaries were changed to encompass land previously part of neighboring Lincoln County. The county seat was moved from Richland to Elk Point on April 30, 1865.

Union County lies on the southeast corner of South Dakota. Its east boundary line abuts the west boundary line of the State of Iowa (across the Big Sioux River), and its south/southwest boundary line abuts the north boundary line of the State of Nebraska (across the Missouri River). The Brule Creek flows southeasterly across the central part of the county, emptying into the Big Sioux. The county terrain consists of rolling hills, devoted to agriculture except around built-up areas.[https://www.google.com/maps/place/Union+County,+SD/@42.6647076,-96.7136853,34319m/data=!3m1!1e3!4m5!3m4!1s0x878e668cae4510e9:0x97256db3797e1b9d!8m2!3d42.8621348!4d-96.7065914 Union County SD Google Maps (accessed February 9, 2019)] The terrain slopes to the south and east; its highest point is near its northwest corner, at {{convert|1,509|ft|m|abbr=on}} ASL.{{Cite web |url=https://www.daftlogic.com/sandbox-google-maps-find-altitude.htm |title="Find an Altitude" Google Maps (accessed February 9, 2019) |access-date=February 9, 2019 |archive-url=https://web.archive.org/web/20190521043409/https://www.daftlogic.com/sandbox-google-maps-find-altitude.htm |archive-date=May 21, 2019 |url-status=dead }} The county has a total area of {{convert|467|sqmi}}, of which {{convert|461|sqmi}} is land and {{convert|6.6|sqmi}} (1.4%) is water.{{cite web|url=http://www2.census.gov/geo/docs/maps-data/data/gazetteer/counties_list_46.txt|publisher=United States Census Bureau|access-date=March 28, 2015|date=August 22, 2012|title=2010 Census Gazetteer Files}} It is the fifth-smallest county in South Dakota by area.

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• 20px Interstate 29
• 20px South Dakota Highway 11
• 20px South Dakota Highway 19
• 20px South Dakota Highway 46
• 20px South Dakota Highway 48
• 20px South Dakota Highway 50
• 23px South Dakota Highway 105

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• Lincoln County to the north
• Sioux County, Iowa to the northeast
• Plymouth County, Iowa to the east
• Woodbury County, Iowa to the southeast
• Dakota County, Nebraska to the south
• Dixon County, Nebraska to the southwest
• Clay County to the west

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• Adams Homestead and State Nature Preserve
• Bent River State Game Production Area
• Bolton State Game Production Area
• Cusick State game Production Area
• Cut Off Bend State Game Production Area
• Missouri National Recreational River (partial)
• Petry-Conway State Game Production Area
• Petry/Harmelink State Game Production Area
• Ryan State Game Production Area
• Union Grove State Park
• Warren Wilderness State Game Production Area

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• Burbank Lake (partial)
• McCook Lake
• Mud Lake

{{US Census population

|1870= 3507

|1880= 6813

|1890= 9130

|1900= 11153

|1910= 10676

|1920= 11099

|1930= 11480

|1940= 11675

|1950= 10792

|1960= 10197

|1970= 9643

|1980= 10938

|1990= 10189

|2000= 12584

|2010= 14399

|2020= 16811

|estyear=2024

|estimate=17402

|estref={{cite web|title=County Population Totals and Components of Change: 2020-2024 |url=https://www.census.gov/data/tables/time-series/demo/popest/2020s-counties-total.html |access-date=March 15, 2025}}

|align-fn=center

|footnote=U.S. Decennial Census{{cite web|title=U.S. Decennial Census |url=https://www.census.gov/programs-surveys/decennial-census.html |publisher=United States Census Bureau |access-date=July 20, 2014}}
1790–1960{{cite web|title=Historical Census Browser |url=http://mapserver.lib.virginia.edu |publisher=University of Virginia Library |url-status=live |date=2007 |access-date=July 20, 2014 |archive-url=https://web.archive.org/web/20091212224028/http://mapserver.lib.virginia.edu/ |archive-date=December 12, 2009}} 1900–1990{{cite web|last=Forstall |first=Richard L. |title=Population of Counties by Decennial Census: 1900 to 1990 |url=https://www.census.gov/population/cencounts/sd190090.txt |publisher=United States Census Bureau |url-status=live |date=March 27, 1995 |access-date=July 20, 2014 |archive-url=https://web.archive.org/web/19990219135447/http://www.census.gov/population/cencounts/sd190090.txt |archive-date=February 19, 1999}}
1990–2000{{cite web|title=Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000 |url=https://www.census.gov/population/www/cen2000/briefs/phc-t4/tables/tab02.pdf |url-status=live |publisher=United States Census Bureau |access-date=July 20, 2014 |archive-url=https://web.archive.org/web/20100327165705/http://www.census.gov/population/www/cen2000/briefs/phc-t4/tables/tab02.pdf |archive-date=March 27, 2010}} 2010–2020

}}

As of the 2020 census, there were 16,811 people, 6,822 households, and 4,613 families in the county.{{Cite web|title=US Census Bureau, Table P16: Household Type |url=https://data.census.gov/table?q=Union%20County,%20South%20Dakota%20p16&y=2020 |access-date=March 20, 2024 |publisher=United States Census Bureau}} The population density was {{convert|36.5|PD/sqmi}}. There were 7,215 housing units.

As of the 2010 census, there were 14,399 people, 5,756 households, and 4,043 families in the county. The population density was {{convert|31.3|PD/sqmi}}. There were 6,280 housing units at an average density of {{convert|13.6|/sqmi}}. The racial makeup of the county was 95.5% white, 0.9% Asian, 0.7% black or African American, 0.6% American Indian, 0.1% Pacific islander, 0.7% from other races, and 1.6% from two or more races. Those of Hispanic or Latino origin made up 2.1% of the population. In terms of ancestry, 42.0% were German, 18.2% were Norwegian, 17.7% were Irish, 7.9% were English, 6.8% were Swedish, and 3.7% were American.

Of the 5,756 households, 32.8% had children under the age of 18 living with them, 58.9% were married couples living together, 7.5% had a female householder with no husband present, 29.8% were non-families, and 25.1% of all households were made up of individuals. The average household size was 2.49 and the average family size was 2.98. The median age was 40.2 years.

The median income for a household in the county was $59,889 and the median income for a family was $71,308. Males had a median income of $42,702 versus $31,993 for females. The per capita income for the county was $33,783. About 3.9% of families and 4.9% of the population were below the poverty line, including 4.3% of those under age 18 and 10.5% of those age 65 or over.

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• Alcester
• Beresford (partial)
• Elk Point (county seat)
• Jefferson
• North Sioux City

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• Dakota Dunes
• Richland

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• Alsen
• Garryowen[http://wikimapia.org/3665681/Garryowen-South-Dakota Garryowen SD (WikiMapia - accessed February 9, 2019)]
• Junction City
• McCook Lake
• Midway
• Nora
• Spink
• Wynstone

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• Emmet
• Gothland (Alcester Twp)
• Hill Side (Emmet Twp)
• Texas (Elk Point Twp)[http://elkpoint.org/about/ Texas Cemetery, Dakota Territory ("About Elk Point" - accessed February 9, 2019)]
• Morganfield{{citation needed|date=February 2019}}

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• Alcester
• Big Sioux
• Big Springs
• Brule
• Civil Bend
• Elk Point
• Emmet
• Jefferson
• Prairie
• Richland
• Sioux Valley
• Spink
• Virginia

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• Richland

Union County voters were more politically centered in times past, but the county has selected the Republican Party candidate in every national election since 2000 (as of 2024).

{{PresHead|place=Union County, South Dakota|whig=no|source1={{cite web|url=http://uselectionatlas.org/RESULTS|title=Atlas of US Presidential Elections|last=Leip|first=David|website=uselectionatlas.org|access-date=April 15, 2018}}}}

{{PresRow|2024|Republican|6,160|2,548|168|South Dakota}}

{{PresRow|2020|Republican|5,944|2,725|186|South Dakota}}

{{PresRow|2016|Republican|5,290|2,227|380|South Dakota}}

{{PresRow|2012|Republican|4,698|2,782|116|South Dakota}}

{{PresRow|2008|Republican|4,310|3,244|147|South Dakota}}

{{PresRow|2004|Republican|3,987|3,000|61|South Dakota}}

{{PresRow|2000|Republican|3,265|2,358|149|South Dakota}}

{{PresRow|1996|Democratic|2,234|2,378|595|South Dakota}}

{{PresRow|1992|Democratic|1,784|2,210|1,103|South Dakota}}

{{PresRow|1988|Democratic|1,907|2,612|31|South Dakota}}

{{PresRow|1984|Republican|2,431|2,221|25|South Dakota}}

{{PresRow|1980|Republican|2,788|1,830|436|South Dakota}}

{{PresRow|1976|Democratic|2,297|2,540|23|South Dakota}}

{{PresRow|1972|Democratic|2,271|2,554|17|South Dakota}}

{{PresRow|1968|Republican|2,212|2,014|225|South Dakota}}

{{PresRow|1964|Democratic|1,727|2,828|0|South Dakota}}

{{PresRow|1960|Republican|2,688|2,331|0|South Dakota}}

{{PresRow|1956|Republican|2,636|2,343|0|South Dakota}}

{{PresRow|1952|Republican|3,393|1,645|0|South Dakota}}

{{PresRow|1948|Democratic|2,205|2,237|23|South Dakota}}

{{PresRow|1944|Republican|2,501|2,057|0|South Dakota}}

{{PresRow|1940|Republican|3,116|2,608|0|South Dakota}}

{{PresRow|1936|Democratic|1,845|3,520|420|South Dakota}}

{{PresRow|1932|Democratic|1,381|3,530|46|South Dakota}}

{{PresRow|1928|Republican|2,415|2,106|19|South Dakota}}

{{PresRow|1924|Republican|1,665|877|1,155|South Dakota}}

{{PresRow|1920|Republican|1,942|841|152|South Dakota}}

{{PresRow|1916|Democratic|1,108|1,313|44|South Dakota}}

{{PresRow|1912|Progressive|0|965|1,504|South Dakota}}

{{PresRow|1908|Republican|1,392|1,009|57|South Dakota}}

{{PresRow|1904|Republican|1,813|730|111|South Dakota}}

{{PresRow|1900|Republican|1,571|1,358|35|South Dakota}}

{{PresRow|1896|Democratic|1,297|1,491|17|South Dakota}}

{{PresFoot|1892|Populist|860|241|885|South Dakota}}

• National Register of Historic Places listings in Union County, South Dakota

{{Reflist}}

• [https://web.archive.org/web/20051118233807/http://www.acsnet.com/~jkjar/ Union County Historical Society website]
• [http://www.progressivefarmer.com/farmer/bestplaces/articles/02union.html 2nd Best Place to Live in 2006] from the Progressive Farmer website

{{Geographic Location

|Centre = Union County, South Dakota

|North = Lincoln County

|Northeast = Sioux County, Iowa

|East = Plymouth County, Iowa

|Southeast = Woodbury County, Iowa

|South = Dakota County, Nebraska

|Southwest = Dixon County, Nebraska

|West = Clay County

}}

{{Union County, South Dakota}}

{{South Dakota}}

{{Authority control}}

{{Coord|42.83|-96.65|display=title|type:adm2nd_region:US-SD_source:UScensus1990}}

Category:1862 establishments in Dakota Territory

Category:Populated places established in 1862

Category:Sioux City metropolitan area

Category:South Dakota counties on the Missouri River