Founded in 1786, Sumner County is one of 95 counties in the state of Tennessee. Historically, Sumner County was formed from Davidson County. The city of Gallatin is the county seat. With FIPS code of 165, Sumner County has a population of 200,557 and area of 529 square miles (1,370 km2).
List of all cities in Sumner County, TN alphabetically
| City/Town | Postal Code | Area Code |
| Bethpage, TN | 37022 | 615 |
| Castalian Springs, TN | 37031 | 615 |
| Cottontown, TN | 37048 | 615 |
| Gallatin, TN | 37066 | 615 |
| Hendersonville, TN | 37075 | 615 |
| 37077 | 615 | |
| Mitchellville, TN | 37119 | 615 |
| Portland, TN | 37148 | 615 |
| Rock Bridge, TN | 37022 | 615 |
| Westmoreland, TN | 37186 | 615 |