| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hartsville | 1 | 7,362 | 7,439 | -0.16% | 1,229 | 6 | City |
| Darlington | 2 | 6,048 | 6,201 | -0.44% | 1,284 | 5 | City |
| Quinby | 3 | 882 | 891 | -0.11% | 675 | 1 | Town |
| Lamar | 4 | 861 | 856 | -0.12% | 710 | 1 | Town |
| Society Hill | 5 | 426 | 434 | -0.47% | 177 | 2 | Town |
Hartsville is the largest city in Darlington County, with a population of 7,362.
Society Hill is the smallest city in Darlington County, with a population of 426.
There are 5 cities in Darlington County, South Carolina.