Corson County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 3,902. Its county seat is McIntosh. The county was named for Dighton Corson, a native of Maine, who came to the Black Hills in 1876, and in 1877 began practicing law at Deadwood.

The county is encompassed within the Standing Rock Indian Reservation, which extends into North Dakota. The Lakota people reside primarily in the South Dakota part of the reservation; the Yanktonai and Dakota live in that part in North Dakota. The Grand River, a tributary of the Missouri River, runs through the reservation.

Geography

Corson County lies on the north line of South Dakota. Its north boundary line abuts the south boundary line of the state of North Dakota. The Missouri River flows south-southeastward along its eastern boundary line. The county terrain consists of semi-arid rolling hills. A portion of the land is dedicated to agriculture. The Grand River flows eastward through the central part of the county to discharge into the river, and Standing Cloud Creek flows eastward through the county's lower SW area. The terrain generally slopes to the east and south; its highest point is near its NW corner, at 2,582 ft (787 m) ASL.

Corson County has a total area of 2,530 square miles (6,600 km), of which 2,470 square miles (6,400 km) is land and 60 square miles (160 km) (2.4%) is water. It is the fifth-largest county in South Dakota by area. The entire county lies within the Standing Rock Indian Reservation, which also includes Sioux, Ziebach, and Dewey counties.

The eastern portion of South Dakota's counties (48 of 66) observe Central Time; the western counties (18 of 66) observe Mountain Time. Corson County is the easternmost of the SD counties to observe Mountain Time.

Major highways

Adjacent counties

Protected areas

• Grand River National Grassland (partial)
• C.C. Lee State Game Production Area

Lakes

Rivers and Streams

• Missouri River
• Grand River
• White Shirt Creek
• Hump Creek
• Stink Creek
• Black Horse Butte Creek
• Soldier Creek
• Firesteel Creek
• Oak Creek
• Rock Creek
• Cottonwood Creek
• High Bank Creek

Peaks

• Hump Butte
• Black Horse Butte
• Rattlesnake Butte
• Elk Butte

Demographics

Historical population

Census	Pop.	Note	%±
1910	2,929		—
1920	7,249		147.5%
1930	9,535		31.5%
1940	6,755		−29.2%
1950	6,168		−8.7%
1960	5,798		−6.0%
1970	4,994		−13.9%
1980	5,196		4.0%
1990	4,195		−19.3%
2000	4,181		−0.3%
2010	4,050		−3.1%
2020	3,902		−3.7%
2023 (est.)	3,782		−3.1%
U.S. Decennial Census 1790-1960 1900-1990 1990-2000 2010-2020

2020 census

As of the 2020 census, there were 3,902 people, 1,196 households, and 825 families residing in the county. The population density was 1.6 inhabitants per square mile (0.62/km). There were 1,362 housing units.

2010 census

As of the 2010 census, there were 4,050 people, 1,260 households, and 939 families in the county. The population density was 1.6 inhabitants per square mile (0.62/km). There were 1,540 housing units at an average density of 0.6 per square mile (0.23/km). The racial makeup of the county was 67.0% American Indian, 29.7% white, 0.3% Asian, 0.1% black or African American, 0.3% from other races, and 2.6% from two or more races. Those of Hispanic or Latino origin made up 2.6% of the population. In terms of ancestry,

Of the 1,260 households, 45.6% had children under the age of 18 living with them, 40.6% were married couples living together, 21.9% had a female householder with no husband present, 25.5% were non-families, and 22.7% of all households were made up of individuals. The average household size was 3.21 and the average family size was 3.73. The median age was 29.7 years.

The median income for a household in the county was $30,877 and the median income for a family was $36,500. Males had a median income of $32,037 versus $23,167 for females. The per capita income for the county was $13,359. About 24.1% of families and 35.1% of the population were below the poverty line, including 46.7% of those under age 18 and 16.9% of those age 65 or over.

Communities

Cities

• McIntosh (county seat)
• McLaughlin

Town

• Morristown

Census-designated places

• Bullhead
• Kenel
• Little Eagle
• Wakpala

Unincorporated communities

Townships

Unorganized territories

Politics

In the 2020 presidential election, Corson County was the county or equivalent with the highest percentage of Native Americans which Donald Trump won, after Joe Biden flipped Ziebach County.

United States presidential election results for Corson County, South Dakota

Year	Republican		Democratic		Third party
	No.	%	No.	%	No.	%
2020	647	50.43%	622	48.48%	14	1.09%
2016	588	50.04%	535	45.53%	52	4.43%
2012	515	42.92%	648	54.00%	37	3.08%
2008	535	38.05%	837	59.53%	34	2.42%
2004	720	41.76%	972	56.38%	32	1.86%
2000	629	50.60%	549	44.17%	65	5.23%
1996	533	41.00%	539	41.46%	228	17.54%
1992	483	38.61%	444	35.49%	324	25.90%
1988	710	49.03%	722	49.86%	16	1.10%
1984	955	54.48%	792	45.18%	6	0.34%
1980	1,233	66.47%	522	28.14%	100	5.39%
1976	846	46.41%	967	53.04%	10	0.55%
1972	975	58.28%	689	41.18%	9	0.54%
1968	1,108	55.15%	821	40.87%	80	3.98%
1964	1,034	43.78%	1,328	56.22%	0	0.00%
1960	1,290	54.13%	1,093	45.87%	0	0.00%
1956	1,394	55.63%	1,112	44.37%	0	0.00%
1952	1,757	69.01%	789	30.99%	0	0.00%
1948	1,154	49.63%	1,154	49.63%	17	0.73%
1944	1,008	56.19%	786	43.81%	0	0.00%
1940	1,709	56.27%	1,328	43.73%	0	0.00%
1936	1,408	42.73%	1,781	54.05%	106	3.22%
1932	946	27.15%	2,403	68.97%	135	3.87%
1928	1,847	56.92%	1,374	42.34%	24	0.74%
1924	1,364	56.50%	140	5.80%	910	37.70%
1920	1,448	60.89%	484	20.35%	446	18.76%
1916	503	42.20%	641	53.78%	48	4.03%
1912	0	0.00%	455	44.26%	573	55.74%

See also

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