County Maps US

Buffalo County, South Dakota

A county in South Dakota, ranked 59 of 66 by population.

CountyFIPS 46017

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

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Population
1,802
-131 (-6.8%) since 2020
Land area
471.4
square miles. A further 3.4% of the total area is water
Population density
3.8
people per square mile, computed rather than published
County seat
Gann Valley
Seat of county government.
Established
1873
152 years ago
Largest city
Not available
No incorporated place lies within this county.

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 Buffalo 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 Buffalo 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 489 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 Buffalo 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
Population1,80259th of 663,057th of 3,144
Land area471.4 sq mi61st of 662,186th of 3,144
Population density3.8 per sq mi44th of 662,840th of 3,144
Median household income$47,04562nd of 662,894th of 3,143

Full data for Buffalo County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population1,802Vintage 2025 Population Estimates
Population in 20201,933Vintage 2025 Population Estimates
2020 estimates base?1,943Vintage 2025 Population Estimates
Land area471.4 sq mi2025 Gazetteer Files
Water area16.4 sq mi2025 Gazetteer Files
Total area487.8 sq mi2025 Gazetteer Files
Population density?3.8 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$47,045American Community Survey 2020-2024 5-Year Estimates
Median home value$117,800American Community Survey 2020-2024 5-Year Estimates
Median age22.8American Community Survey 2020-2024 5-Year Estimates
Households508American Community Survey 2020-2024 5-Year Estimates
Housing units578American 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
+6
32 births, 26 deaths
Net migration
-12
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 5 areas bordering Buffalo 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
Lyman CountySouth Dakota25 mi3,694
Brule CountySouth Dakota21 mi5,278
Hand CountySouth Dakota19 mi3,121
Jerauld CountySouth Dakota18 mi1,654
Hyde CountySouth Dakota14 mi1,191

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.