Fall River County is a county in South Dakota, United States, in the southwest corner of the state along the Nebraska and Wyoming lines. It had a population of 6,973 at the 2020 census and covers 1,749 square miles (4,530 km2) centred near 43°15′N 103°31′W.
Hot Springs is the county seat; its postal code is 57747. The county has 3 incorporated cities and towns, 7 census-designated places, several unincorporated communities and 3 organized townships. Fall River County is in the Mountain time zone.
Towns & Villages in Fall River County
Fall River County has 20 named places on record, split between 3 incorporated cities and towns and a larger set of census-designated places and unincorporated communities. CDPs (Census-Designated Places) are unincorporated but recognized by the Census Bureau; Unincorp. entries have no local government of their own.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Hot Springs | City · seat | 3,711 | 57747 |
| Edgemont | City | 620 | 57735 |
| Oelrichs | Town | 147 | 57763 |
| Angostura | CDP | — | — |
| Ardmore | CDP | — | — |
| Dudley | CDP | — | — |
| Maverick Junction | CDP | — | — |
| Oral | CDP | — | 57766 |
| Provo | CDP | — | — |
| Smithwick | CDP | — | 57782 |
| Rumford | Unincorp. | — | — |
| Burdock | Unincorp. · ghost town | — | — |
| Cascade Springs | Unincorp. · ghost town | — | — |
| Heppner | Unincorp. · ghost town | — | — |
| Igloo | Unincorp. · former ordnance depot | — | — |
| Marietta | Unincorp. | — | — |
| Minnekahta | Unincorp. | — | — |
| Rocky Ford | Unincorp. | — | — |
| Dennis | Unincorp. | — | — |
| Erskine | Unincorp. | — | — |
Igloo is a former U.S. Army ordnance depot townsite southeast of Edgemont, largely abandoned since the depot closed in the 1960s. Burdock, Cascade Springs and Heppner are historic communities now considered ghost towns, kept in the list because their names still mark places on county maps.
Townships
| Township | Main settlements |
|---|---|
| Provo | Provo |
| Argentine | Rumford area |
| Robins | rural, no named town |
ZIP Codes
- 57747 — Hot Springs (also serves Angostura, Minnekahta, Cascade Springs)
- 57735 — Edgemont (also serves Igloo, Rumford)
- 57763 — Oelrichs
- 57766 — Oral
- 57782 — Smithwick (PO Box service only)
Ardmore, Dudley, Maverick Junction and Provo use the ZIP code of their nearest post-office town rather than one of their own.
Geography
Fall River County sits on the southwestern edge of the Black Hills, where pine-covered hills give way to the mixed-grass prairie of the southern Black Hills foothills. The Cheyenne River crosses the county’s north end, and the Fall River, for which the county is named, runs through Hot Springs. Angostura Reservoir, formed by a dam on the Cheyenne River, is the county’s largest body of water and a state recreation area.
Fall River County borders Custer County to the north and Oglala Lakota County to the east, both in South Dakota; Dawes County to the southeast and Sioux County to the south, both in Nebraska; and Niobrara County, Wyoming, to the west.
Demographics
The county’s population was 6,973 at the 2020 census. Hot Springs and Edgemont are the two largest communities. Fall River County’s median household income runs well below the South Dakota median of $71,810, reflecting its small, aging, rural population base. Density works out to roughly 4 people per square mile of land, among the lowest in the state.
Economy & Local Life
Tourism, ranching and government services anchor the local economy. Hot Springs takes its name from the warm mineral springs that drew Native Americans and later health-seeking settlers; the Battle Mountain Sanitarium (now a VA medical center) and Mammoth Site — a working paleontological dig and museum built around a Ice Age sinkhole trap — are the county’s best-known institutions. Cattle ranching dominates the open range outside Hot Springs and Edgemont, and Angostura Reservoir draws boaters and anglers from across the southern Black Hills each summer.
History
Fall River County was organized in 1883 and named for the Fall River, a spring-fed stream that flows through Hot Springs. Hot Springs grew around its mineral springs as a resort and health destination beginning in the 1880s; the Evans Plunge indoor pool, built over one of the springs, has operated continuously since 1890. Igloo, in the county’s southeast, was built during World War II as the Black Hills Ordnance Depot and functioned as an Army ammunition storage site until it closed in the 1960s.
Getting There
- Rapid City — 55 miles north
- Chadron, Nebraska — 45 miles southeast
- Newcastle, Wyoming — 55 miles west
- Custer, South Dakota — 35 miles north
US Highway 18 and US Highway 385 cross at Hot Springs, the county’s main road junction. The nearest commercial airport is Rapid City Regional Airport.
Frequently Asked Questions
Where is Fall River County?
It is in the southwest corner of South Dakota, bordering Nebraska and Wyoming.
What is the population of Fall River County?
6,973 at the 2020 census.
How big is Fall River County?
1,749 square miles (4,530 km2), including 9.2 square miles of water.
What is the county seat of Fall River County?
Hot Springs is the county seat.
How many towns are in Fall River County?
Three incorporated cities and towns — Hot Springs, Edgemont and Oelrichs — plus several unincorporated communities and CDPs.
What ZIP codes are in Fall River County?
57747 (Hot Springs), 57735 (Edgemont), 57763 (Oelrichs), 57766 (Oral) and 57782 (Smithwick).
Why is it called Fall River County?
It is named for the Fall River, a spring-fed stream that runs through Hot Springs.
More counties in this state: Towns and villages in South Dakota.