Douglas County is a county in South Dakota, United States, on the rolling prairie of the James River lowlands. It had a population of 2,835 at the 2020 census and covers 434 square miles (1,124 km2) centred near 43°23′N 98°22′W.
Armour is the county seat, and its postal code is 57313. The county has three incorporated cities, three census-designated places, and several small unincorporated communities. Douglas County observes Central Time and has South Dakota’s second-smallest land area of any county.
Towns & Villages in Douglas County
Eight named places appear on maps of Douglas County: three incorporated cities and five unincorporated or census-designated communities. CDP = census-designated place; Unincorp. = unincorporated community with no separate municipal government.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Armour | City · seat | 693 | 57313 |
| Corsica | City | 582 | 57328 |
| Delmont | City | 238 | 57330 |
| Greenwood Colony | CDP | — | 57313 |
| Harrison | CDP | — | 57313 |
| New Holland | CDP | — | 57328 |
| Hillside | Unincorp. | — | — |
| Joubert | Unincorp. | — | — |
Two ghost towns, Douglas City and Flensburg, once had post offices in the county but no longer appear as populated places.
ZIP Codes
- 57313 — Armour (also serves Greenwood Colony and Harrison)
- 57328 — Corsica (also serves New Holland)
- 57330 — Delmont
Hillside and Joubert have no dedicated post office and are served by mail routes out of the nearest incorporated city.
Geography
Douglas County sits on rolling hills used mostly for grain and cattle farming. The land rises toward the county’s southwest corner, where the highest point reaches 1,677 feet (511 m) above sea level, then falls away to the east toward the James River valley. Water covers only 1.9 square miles of the county’s total area, mostly small stock ponds and drainage creeks rather than any single named lake. The county has no organized civil townships; local government runs through the county commission and the incorporated cities.
Douglas County borders Aurora County to the north, Davison County to the northeast, Hutchinson County to the east, and Charles Mix County to the southwest. The James River corridor running through neighboring Davison and Hutchinson counties shapes the drainage pattern along Douglas County’s own eastern edge.
Demographics
The 2020 census counted 2,835 residents, a density of about 6.6 people per square mile. Armour and Corsica are the county’s two largest communities. Douglas County’s median household income runs well below the South Dakota median of $71,810, typical of the state’s smaller farm counties. About 23% of residents are under 18 and roughly 27% are 65 or older.
Economy & Local Life
Grain farming and cattle ranching drive the county economy, with corn, soybeans and wheat as the main crops and grain elevators anchoring each town’s Main Street. Armour serves as the retail and services hub, home to the Douglas County courthouse, the Douglas County Fair each summer, and the Armour School District. Corsica and Delmont each retain a small-town main street with a school, grain elevator, and local businesses serving the surrounding farms. Like much of rural South Dakota, the county’s population has declined slowly over recent decades as farm consolidation reduces the need for on-farm labor.
History
Douglas County was established in 1873 and organized in 1882. It takes its name from Stephen A. Douglas, the Illinois senator and 1860 presidential candidate. Settlement followed the railroad’s arrival in the 1880s, which founded Armour and Corsica as shipping points for the surrounding wheat farms. Two early post-office communities, Douglas City and Flensburg, did not survive as the railroad favored Armour and Corsica instead, and both faded into ghost towns by the early twentieth century. Since South Dakota statehood in 1889, Douglas County has remained one of the state’s smaller counties by population, its fortunes tied closely to Great Plains grain prices.
Getting There
U.S. Route 281 runs north–south through the county, and South Dakota Highway 46 crosses it east–west through Armour.
- Mitchell — 25 miles northeast
- Wagner — 30 miles southwest
- Sioux Falls — 90 miles east
The nearest commercial airport is Mitchell Municipal Airport; Joe Foss Field in Sioux Falls offers wider connections.
Frequently Asked Questions
Where is Douglas County, South Dakota?
It lies in south-central South Dakota, between the James River valley and the Missouri River bluffs, about 25 miles southwest of Mitchell.
What is the population of Douglas County?
2,835 people, per the 2020 census.
How big is Douglas County?
434 square miles (1,124 km2), the second-smallest land area of any South Dakota county.
What is the Douglas County seat?
Armour is the county seat.
How many towns are in Douglas County?
Three incorporated cities — Armour, Corsica and Delmont — plus several smaller unincorporated communities.
What ZIP codes are in Douglas County?
57313 (Armour), 57328 (Corsica) and 57330 (Delmont).
Who is Douglas County named after?
Illinois senator Stephen A. Douglas, best known for his 1858 debates with Abraham Lincoln.
More counties in this state: Towns and villages in South Dakota.