Barnwell County, South Carolina
A county in South Carolina, ranked 38 of 46 by population.
CountyFIPS 45011
- Population
- 20,653
- +73 (+0.4%) since 2020
- Land area
- 548.4
- square miles. A further 1.6% of the total area is water
- Population density
- 37.7
- people per square mile, computed rather than published
- County seat
- Barnwell
- Seat of county government.
- Established
- 1800
- 225 years ago
- Largest city
- Barnwell city
- Population 4,619.
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 Barnwell 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 Barnwell County ranks
Position among the 46 counties of South Carolina, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.
| Measure | Value | In South Carolina | Nationally |
|---|---|---|---|
| Population | 20,653 | 38th of 46 | 1,796th of 3,144 |
| Land area | 548.4 sq mi | 31st of 46 | 1,903rd of 3,144 |
| Population density | 37.7 per sq mi | 38th of 46 | 1,724th of 3,144 |
| Median household income | $46,626 | 36th of 46 | 2,914th of 3,143 |
Full data for Barnwell County
| Measure | Value | Source and vintage |
|---|---|---|
| Population | 20,653 | Vintage 2025 Population Estimates |
| Population in 2020 | 20,580 | Vintage 2025 Population Estimates |
| 2020 estimates base? | 20,583 | Vintage 2025 Population Estimates |
| Land area | 548.4 sq mi | 2025 Gazetteer Files |
| Water area | 8.9 sq mi | 2025 Gazetteer Files |
| Total area | 557.3 sq mi | 2025 Gazetteer Files |
| Population density? | 37.7 per sq mi | Computed: Vintage 2025 estimates divided by 2025 Gazetteer land area |
| Median household income | $46,626 | American Community Survey 2020-2024 5-Year Estimates |
| Median home value | $106,000 | American Community Survey 2020-2024 5-Year Estimates |
| Median age | 40.4 | American Community Survey 2020-2024 5-Year Estimates |
| Households | 8,116 | American Community Survey 2020-2024 5-Year Estimates |
| Housing units | 9,927 | 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
- 0
- 283 births, 283 deaths
- Net migration
- +142
- More people moved in than moved out.
Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.
The 5 areas bordering Barnwell 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 |
|---|---|---|---|
| Aiken County | South Carolina | 30 mi | 181,515 |
| Allendale County | South Carolina | 27 mi | 7,355 |
| Bamberg County | South Carolina | 24 mi | 12,796 |
| Orangeburg County | South Carolina | 16 mi | 83,177 |
| Burke County | Georgia | 14 mi | 24,408 |
Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.
All 46 counties of South Carolina
Open the interactive South Carolina county map, or jump straight to any of them.
- Abbeville County
- Aiken County
- Allendale County
- Anderson County
- Bamberg County
- Barnwell County
- Beaufort County
- Berkeley County
- Calhoun County
- Charleston County
- Cherokee County
- Chester County
- Chesterfield County
- Clarendon County
- Colleton County
- Darlington County
- Dillon County
- Dorchester County
- Edgefield County
- Fairfield County
- Florence County
- Georgetown County
- Greenville County
- Greenwood County
- Hampton County
- Horry County
- Jasper County
- Kershaw County
- Lancaster County
- Laurens County
- Lee County
- Lexington County
- Marion County
- Marlboro County
- McCormick County
- Newberry County
- Oconee County
- Orangeburg County
- Pickens County
- Richland County
- Saluda County
- Spartanburg County
- Sumter County
- Union County
- Williamsburg County
- York County
Data on this page last rebuilt 30 August 2026. How these figures are produced.