4 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Smithville | 1 | 5,625 | 5,042 | 2.12% | 961 | 5.85 | City |
| Alexandria | 2 | 994 | 984 | 0.2% | 491 | 2.02 | Town |
| Dowelltown | 3 | 372 | 344 | 1.64% | 495 | 0.75 | Town |
| Liberty | 4 | 343 | 332 | 0.59% | 297 | 1.16 | Town |
Smithville is the largest city in DeKalb County, with a population of 5,625.
Liberty is the smallest city in DeKalb County.
There are 4 cities in DeKalb County, Tennessee.