Fall River County lies at South Dakota's SW corner. Its south borderline abuts the north borderline of the state of Nebraska, and its west borderline abuts the east borderline of the state of Wyoming. The Fall River County terrain contains a mountainous area in the north-central portion, with rolling hills in the rest of the county. Outside the mountainous area, the county's highest point is its SW corner, at 3,970 ft (1,210 m) ASL. Of the several peaks in the mountainous area, one in the NE portion of that zone rises to 4,646 ft (1,416 m) ASL. The terrain slopes to the north and east. Discharging from the Angostura Reservoir, the Cheyenne River flows northeasterly through the upper part of the county, departing the county through its north boundary line into Custer County.
Fall River County has a total area of 1,749 square miles (4,530 km2), of which 1,740 square miles (4,500 km2) is land and 9.2 square miles (24 km2) (0.5%) is water.[4]
U.S. Decennial Census[6] 1790-1960[7] 1900-1990[8] 1990-2000[9] 2010-2020[1]
2020 census
As of the 2020 census, there were 6,973 people, 3,226 households, and 1,891 families residing in the county.[10] The population density was 4.0 inhabitants per square mile (1.5/km2). There were 4,081 housing units.
2010 census
As of the 2010 census, there were 7,094 people, 3,272 households, and 1,899 families in the county. The population density was 4.1 inhabitants per square mile (1.6/km2). There were 4,191 housing units at an average density of 2.4 units per square mile (0.93 units/km2). The racial makeup of the county was 88.6% white, 7.1% American Indian, 0.7% black or African American, 0.4% Asian, 0.3% from other races, and 2.9% from two or more races. Those of Hispanic or Latino origin made up 2.2% of the population. In terms of ancestry, 39.7% were German, 12.6% were Irish, 11.2% were English, 8.4% were Norwegian, 5.9% were Dutch, and 2.3% were American.
Of the 3,272 households, 20.4% had children under the age of 18 living with them, 46.2% were married couples living together, 8.9% had a female householder with no husband present, 42.0% were non-families, and 37.6% of all households were made up of individuals. The average household size was 2.10 and the average family size was 2.74. The median age was 50.5 years.
The median income for a household in the county was $35,833 and the median income for a family was $53,750. Males had a median income of $36,495 versus $32,058 for females. The per capita income for the county was $21,574. About 11.4% of families and 17.4% of the population were below the poverty line, including 11.3% of those under age 18 and 21.3% of those age 65 or over.
Fall River voters have been reliably Republican for decades. In no national election since 1936 has the county selected the Democratic Party presidential candidate.
United States presidential election results for Fall River County, South Dakota[12]
