County Maps US

Grant County, South Dakota

A county in South Dakota, ranked 23 of 66 by population.

CountyFIPS 46051

Within South Dakota
Grant County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data. The dot marks Milbank, the county seat, located via the 2025 Census Gazetteer.

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Population
7,534
-3 (0%) since 2020
Land area
681.4
square miles. A further 0.9% of the total area is water
Population density
11.1
people per square mile, computed rather than published
County seat
Milbank
Seat of county government.
Established
1873
152 years ago
Largest city
Milbank city
Population 3,512.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Grant County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Grant County, South Dakota from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 800 by 545 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Grant County ranks

Position among the 66 counties of South Dakota, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn South DakotaNationally
Population7,53423rd of 662,610th of 3,144
Land area681.4 sq mi48th of 661,376th of 3,144
Population density11.1 per sq mi19th of 662,527th of 3,144
Median household income$75,02821st of 66839th of 3,143

Full data for Grant County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population7,534Vintage 2025 Population Estimates
Population in 20207,537Vintage 2025 Population Estimates
2020 estimates base?7,561Vintage 2025 Population Estimates
Land area681.4 sq mi2025 Gazetteer Files
Water area6.1 sq mi2025 Gazetteer Files
Total area687.5 sq mi2025 Gazetteer Files
Population density?11.1 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$75,028American Community Survey 2020-2024 5-Year Estimates
Median home value$171,000American Community Survey 2020-2024 5-Year Estimates
Median age44.5American Community Survey 2020-2024 5-Year Estimates
Households3,029American Community Survey 2020-2024 5-Year Estimates
Housing units3,456American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
-34
84 births, 118 deaths
Net migration
-45
More people moved out than moved in.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 6 areas bordering Grant County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Roberts CountySouth Dakota38 mi10,255
Codington CountySouth Dakota29 mi29,562
Deuel CountySouth Dakota21 mi4,408
Lac qui Parle CountyMinnesota20 mi6,704
Day CountySouth Dakota10 mi5,484
Big Stone CountyMinnesota4.3 mi5,054

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

All 66 counties of South Dakota

Open the interactive South Dakota county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.