Lyman County, South Dakota
A county in South Dakota, ranked 43 of 66 by population.
CountyFIPS 46085
- Population
- 3,694
- -3 (-0.1%) since 2020
- Land area
- 1,642
- square miles. A further 3.8% of the total area is water
- Population density
- 2.3
- people per square mile, computed rather than published
- County seat
- Kennebec
- Seat of county government.
- Established
- 1873
- 152 years ago
- Largest city
- Presho city
- Population 463.
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 Lyman 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.
Where Lyman 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.
| Measure | Value | In South Dakota | Nationally |
|---|---|---|---|
| Population | 3,694 | 43rd of 66 | 2,906th of 3,144 |
| Land area | 1,642 sq mi | 14th of 66 | 367th of 3,144 |
| Population density | 2.3 per sq mi | 51st of 66 | 2,963rd of 3,144 |
| Median household income | $67,143 | 43rd of 66 | 1,420th of 3,143 |
Full data for Lyman County
| Measure | Value | Source and vintage |
|---|---|---|
| Population | 3,694 | Vintage 2025 Population Estimates |
| Population in 2020 | 3,697 | Vintage 2025 Population Estimates |
| 2020 estimates base? | 3,714 | Vintage 2025 Population Estimates |
| Land area | 1,642 sq mi | 2025 Gazetteer Files |
| Water area | 64.6 sq mi | 2025 Gazetteer Files |
| Total area | 1,707 sq mi | 2025 Gazetteer Files |
| Population density? | 2.3 per sq mi | Computed: Vintage 2025 estimates divided by 2025 Gazetteer land area |
| Median household income | $67,143 | American Community Survey 2020-2024 5-Year Estimates |
| Median home value | $165,800 | American Community Survey 2020-2024 5-Year Estimates |
| Median age | 36.1 | American Community Survey 2020-2024 5-Year Estimates |
| Households | 1,188 | American Community Survey 2020-2024 5-Year Estimates |
| Housing units | 1,553 | American 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
- +24
- 60 births, 36 deaths
- Net migration
- -21
- 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 10 areas bordering Lyman 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 area | State | Shared border | Population |
|---|---|---|---|
| Tripp County | South Dakota | 84 mi | 5,708 |
| Brule County | South Dakota | 42 mi | 5,278 |
| Jones County | South Dakota | 33 mi | 913 |
| Hughes County | South Dakota | 33 mi | 17,570 |
| Buffalo County | South Dakota | 25 mi | 1,802 |
| Stanley County | South Dakota | 23 mi | 3,018 |
| Gregory County | South Dakota | 12 mi | 4,037 |
| Mellette County | South Dakota | 7.7 mi | 2,137 |
| Hyde County | South Dakota | 4.8 mi | 1,191 |
| Charles Mix County | South Dakota | 75 ft | 9,303 |
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.
- Aurora County
- Beadle County
- Bennett County
- Bon Homme County
- Brookings County
- Brown County
- Brule County
- Buffalo County
- Butte County
- Campbell County
- Charles Mix County
- Clark County
- Clay County
- Codington County
- Corson County
- Custer County
- Davison County
- Day County
- Deuel County
- Dewey County
- Douglas County
- Edmunds County
- Fall River County
- Faulk County
- Grant County
- Gregory County
- Haakon County
- Hamlin County
- Hand County
- Hanson County
- Harding County
- Hughes County
- Hutchinson County
- Hyde County
- Jackson County
- Jerauld County
- Jones County
- Kingsbury County
- Lake County
- Lawrence County
- Lincoln County
- Lyman County
- Marshall County
- McCook County
- McPherson County
- Meade County
- Mellette County
- Miner County
- Minnehaha County
- Moody County
- Oglala Lakota County
- Pennington County
- Perkins County
- Potter County
- Roberts County
- Sanborn County
- Spink County
- Stanley County
- Sully County
- Todd County
- Tripp County
- Turner County
- Union County
- Walworth County
- Yankton County
- Ziebach County
Data on this page last rebuilt 30 August 2026. How these figures are produced.