Grant County is a county in South Dakota, United States, on the Minnesota border in the east-central part of the state. It had a population of 7,556 at the 2020 census and covers 688 square miles (1,780 km2), of which 6.1 square miles is water, centred near 45°10′N 96°46′W.
Milbank is the county seat, and its postal code is 57252. The county has 2 cities, 7 towns and 1 unincorporated community. Grant County observes Central time.
Towns & Villages in Grant County
Ten named places are recognized in Grant County: two cities (Milbank, the seat, and Big Stone City), seven towns, and the unincorporated community of Troy. The table below lists each with its type and ZIP code; population figures marked — were not independently verifiable at the time of writing.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Milbank | City · seat | — | 57252 |
| Big Stone City | City | — | 57216 |
| Albee | Town | — | 57252 |
| La Bolt | Town | — | 57246 |
| Marvin | Town | — | 57251 |
| Revillo | Town | — | 57259 |
| Stockholm | Town | — | 57264 |
| Strandburg | Town | — | 57265 |
| Twin Brooks | Town | — | 57269 |
| Troy | Unincorp. | — | 57252 |
The old county listing carried both “La Bolt town” and “LaBolt” as separate entries; they are the same place, Albee’s neighbor to the north, and are merged here as La Bolt.
ZIP Codes
- 57252 — Milbank (also serves Albee and Troy)
- 57216 — Big Stone City
- 57246 — La Bolt
- 57251 — Marvin
- 57259 — Revillo
- 57264 — Stockholm
- 57265 — Strandburg
- 57269 — Twin Brooks
Albee and Troy have no post office of their own and are served out of the Milbank ZIP.
Geography
Grant County’s terrain is rolling hills that slope toward the northeast, with agriculture dominating the landscape. Big Stone Lake, on the county’s eastern edge, marks South Dakota’s lowest point of elevation, near where the lake drains into the Minnesota River at Ortonville.
Grant County borders Roberts County to the north, Deuel County to the south, Day County to the west, and Big Stone County and Lac qui Parle County, both in Minnesota, to the east across the state line.
The county sits within the Coteau des Prairies, a broad plateau of glacial hills running through eastern South Dakota, which accounts for the rolling relief that distinguishes it from the flatter farmland just across the Minnesota line. The climate is continental, with cold, snowy winters and warm, humid summers typical of the northern Plains.
Demographics
Grant County’s population was 7,556 at the 2020 census. Milbank and Big Stone City are the county’s two largest communities. South Dakota’s 2023 median household income is $71,810; county-level income data was not independently verified for this update. Population density works out to roughly 11 people per square mile.
Economy & Local Life
Agriculture, chiefly corn, soybeans and cattle, is the backbone of Grant County’s economy, supplemented by grain handling and farm-equipment dealers based in Milbank. Grain elevators along the county’s rail lines still move much of the harvest to market each fall. Big Stone Lake draws anglers and boaters to the county’s eastern shore in summer, and the surrounding coteau ridges have attracted wind-energy development typical of the region.
History
Grant County was established in 1873 and organized on January 8, 1878. It is named for Ulysses S. Grant, the 18th President of the United States, who was in office at the time of the county’s founding. Milbank grew up as a railroad town on the line that pushed west from Minnesota in the 1880s, and its rail connections shaped where the county’s other towns, including Big Stone City, Revillo and Marvin, were platted along the tracks. Like much of rural eastern South Dakota, the county’s population peaked in the early-to-mid 20th century and has declined gradually since as farms consolidated.
Getting There
U.S. Route 12 crosses the county through Milbank and Big Stone City. Selected distances from Milbank:
- Watertown, South Dakota — 45 miles southwest
- Sisseton, South Dakota — 30 miles north
- Ortonville, Minnesota — 15 miles east
- Sioux Falls, South Dakota — 130 miles south
The nearest commercial airport is Watertown Regional Airport, about 45 miles southwest of Milbank.
Frequently Asked Questions
Where is Grant County, South Dakota?
It sits in the east-central part of the state, on the Minnesota border, roughly 45 miles northeast of Watertown.
What is the population of Grant County?
7,556 people, per the 2020 census.
How big is Grant County?
688 square miles (1,780 km2), including 6.1 square miles of water.
What is the county seat of Grant County?
Milbank.
How many towns are in Grant County?
Nine incorporated places (two cities and seven towns) plus the unincorporated community of Troy.
What ZIP codes are in Grant County?
57252 (Milbank), 57216 (Big Stone City), 57246 (La Bolt), 57251 (Marvin), 57259 (Revillo), 57264 (Stockholm), 57265 (Strandburg) and 57269 (Twin Brooks).
Why is Grant County named after Ulysses S. Grant?
It was established in 1873, five years into Grant’s presidency, and was named to honor him.
More counties in this state: Towns and villages in South Dakota.