4 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Smithville | 1 | 5,797 | 5,044 | 2.22% | 990 | 6 | City |
| Alexandria | 2 | 958 | 915 | 0.74% | 794 | 1 | Town |
| Dowelltown | 3 | 378 | 344 | 1.61% | 503 | 1 | Town |
| Liberty | 4 | 351 | 333 | 0.86% | 304 | 1 | Town |
Smithville is the largest city in DeKalb County, with a population of 5,797.
Liberty is the smallest city in DeKalb County, with a population of 351.
There are 4 cities in DeKalb County, Tennessee.