Sanborn County is a county in South Dakota, United States, on the James River plain of the state’s east-central prairie. It had a population of 2,330 at the 2020 census and covers 569 square miles (1,470 km2) of land plus 1.2 square miles (3.1 km2) of water, centred near 44°02′N 98°05′W.
Woonsocket is the county seat, and its postal code is 57385. The county has one incorporated city, two incorporated towns, two census-designated places and one unincorporated community, spread across 16 civil townships. Sanborn County is in the Central time zone; its FIPS code is 46-111.
Towns & Villages in Sanborn County
Sanborn County has six named settlements: one city (the county seat), two towns, two census-designated places (CDPs) and one unincorporated place. All are small farm-service communities strung along the county’s rail lines and state highways.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Woonsocket | City · seat | Woonsocket | 631 | 57385 |
| Artesian | Town | Diana | 129 | 57314 |
| Letcher | Town | Letcher | 159 | 57359 |
| Forestburg | CDP | Twin Lake | — | — |
| Upland Colony | CDP | Warren | — | — |
| Cuthbert | Unincorp. | Union | — | — |
Forestburg and Upland Colony are census-designated places rather than incorporated towns, so the Census Bureau tracks their population but the state does not. Cuthbert is an unincorporated crossroads community with no current population figure. The old site listing repeated “Upland Colony” twice and dropped “Ruskin Park,” an informal historical name with no independent record — both corrected here.
Geography
Sanborn County sits on rolling glacial till prairie, farmed almost edge to edge. The James River flows south through the east-central part of the county, and Dry Run Creek drains the southwest. Land slopes generally south and southeast; the county’s highest point, 1,358 feet (414 m) above sea level, is in the southwest corner. Sanborn County borders Beadle County to the north, Kingsbury County to the northeast, Miner County to the east, Hanson County to the southeast, Davison County to the south, Aurora County to the southwest, and Jerauld County to the west.
Bordering counties: Beadle County (north), Kingsbury County (northeast), Miner County (east), Hanson County (southeast), Davison County (south), Aurora County (southwest), and Jerauld County (west).
Demographics
Sanborn County counted 2,330 residents at the 2020 census, giving a density of roughly 4.1 people per square mile — one of South Dakota’s more sparsely populated counties. Woonsocket is the largest community at 631 people, followed by Letcher at 159 and Artesian at 129. County-level income figures are not independently confirmed here; South Dakota’s 2023 ACS median household income was $71,810, and rural counties like Sanborn typically run below the state figure.
Economy & Local Life
Agriculture drives the county’s economy — corn, soybeans, wheat and cattle on land that has been farmed continuously since the 1880s. Woonsocket serves as the trade center for grain elevators, farm-equipment dealers and the county’s schools and offices. The Sanborn County Fair, held in Forestburg, is the county’s best-known annual gathering.
History
The Dakota Territorial legislature created Sanborn County on May 1, 1883, from land taken out of Miner County, and county government was organized by July 18 of that year. It is named for George W. Sanborn, a member of the territorial legislature. An early curiosity in the county’s history: inventor E. S. Callihan built and ran a steam-powered automobile in Woonsocket in 1884, decades ahead of the mass-market car.
Getting There
South Dakota Highways 34, 37 and 224 cross the county, connecting Woonsocket to the surrounding region.
- Mitchell — 30 miles south
- Huron — 30 miles north
- Sioux Falls — 90 miles southeast
- De Smet — 25 miles northeast
The nearest commercial airport is Joe Foss Field in Sioux Falls.
Frequently Asked Questions
Where is Sanborn County, South Dakota?
It is in east-central South Dakota, on the James River plain between Huron and Mitchell.
What is the population of Sanborn County?
2,330 at the 2020 census.
How big is Sanborn County?
569 square miles (1,470 km2) of land, plus 1.2 square miles (3.1 km2) of water.
What is the county seat of Sanborn County?
Woonsocket, the county’s largest city.
How many towns are in Sanborn County?
One city, two towns, two census-designated places and one unincorporated community — six named places in all.
What ZIP codes are in Sanborn County?
57385 (Woonsocket), 57314 (Artesian) and 57359 (Letcher).
What river runs through Sanborn County?
The James River, which flows south through the east-central part of the county.
More counties in this state: Towns and villages in South Dakota.