4 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Smithville | 1 | 5,671 | 5,044 | 2.25% | 969 | 6 | City |
| Alexandria | 2 | 951 | 915 | 0.74% | 470 | 2 | Town |
| Dowelltown | 3 | 372 | 344 | 1.36% | 495 | 1 | Town |
| Liberty | 4 | 348 | 333 | 0.87% | 301 | 1 | Town |
Smithville is the largest city in DeKalb County, with a population of 5,671.
Liberty is the smallest city in DeKalb County, with a population of 348.
There are 4 cities in DeKalb County, Tennessee.