Founded in 1837, DeKalb County is one of 95 counties in the state of Tennessee. Historically, DeKalb County was formed from Franklin, Cannon, Jackson and White counties. The city of Smithville is the county seat. With FIPS code of 41, DeKalb County has a population of 20,478 and area of 304 square miles (787 km2).
List of all cities in DeKalb County, TN alphabetically
| City/Town | Postal Code | Area Code |
| Alexandria, TN | 37012 | 615 |
| Dowelltown, TN | 37059 | 615 |
| Gassaway, TN | 37095 | 615 |
| Liberty, TN | 37095 | 615 |
| Smithville, TN | 37166 | 615 |