| County: | Fall River County |
| State: | South Dakota |
| Ex Image: | 7413a sm.jpg |
| Ex Image Cap: | Battle Mountain Sanitarium in Hot Springs. |
| Founded Date: | April 3 |
| Founded Year: | 1883 |
| Seat Wl: | Hot Springs |
| Largest City Wl: | Hot Springs |
| Area Total Sq Mi: | 1749 |
| Area Land Sq Mi: | 1740 |
| Area Water Sq Mi: | 9.2 |
| Area Percentage: | 0.5 |
| Population As Of: | 2020 |
| Population Total: | 6973 |
| Pop Est As Of: | 2023 |
| Population Est: | 7393 |
| Population Density Sq Mi: | auto |
| Time Zone: | Mountain |
| Web: | http://fallriver.sdcounties.org/ |
| District: | At-large |
Fall River County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 6,973.[1] Its county seat is Hot Springs.[2] The county was founded in 1883. It is named for Fall River which runs through it.[3]
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 3970feet ASL. Of the several peaks in the mountainous area, one in the NE portion of that zone rises to 4646feet 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, of which is land and (0.5%) is water.[4]
As of the 2020 census, there were 6,973 people, 3,226 households, and 1,891 families residing in the county.[5] The population density was . There were 4,081 housing units.
As of the 2010 census, there were 7,094 people, 3,272 households, and 1,899 families in the county. The population density was . There were 4,191 housing units at an average density of 2.4/mi2. 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 candidate.