| ZIP Codes: | 5 ZIP Codes (3 Standard, 2 PO Box, 0 Unique) [See All] |
| Area Codes: | 803 / 839 |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:13:38 PM |
| Population: | 21,456 [See All] |
| FIPS: | 45011 |
| Land Area: | 566 sq mi |
| Water Area: | 4 sq mi |
| Coordinates: | 33.3090, -81.3867 |
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21,456 residents live across 5 ZIPs covering 566 sq mi, served by 5 distinct USPS-recognized cities.
Population moved from 23,358 to 21,456 from 2014 to 2024 — a -8.1% change. 1 ZIPs gained residents, 3 lost.
The county's wealthiest ZIP 29812 (Barnwell, $51,870 median) and poorest ZIP 29817 (Blackville, $41,579) are 14.2 miles apart — a 1.2× income gap across local geography.
Median home values vary 1.4× across this county — from $78,600 in 29826 (Elko) to $112,900 in 29812 (Barnwell).
Density varies 2× across the county — from 25 people/sq mi in 29853 (Williston) to 51 in 29812 (Barnwell).
Educational attainment ranges from 3.7% bachelor's+ in 29826 (Elko) to 15.3% in 29812 (Barnwell) — the breadth of educational profiles across the area.
Within South Carolina, this is the #38 most populous of 46 counties and ranks #40 for median household income .
Weighted by population, the typical household earns about $47,933 across the county — reflecting what a typical resident sees, not a simple ZIP average.
13.7% of adults age 25+ hold a bachelor's degree or higher (2,004 of 14,596 reporting).
3 Standard delivery, 2 PO Box only, 0 single-entity Unique ZIPs serve this county.
A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.
Barnwell County lost 8.1% of residents between 2014 and 2024. ZIPs that shed the largest share: