9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hendersonville | 1 | 64,404 | 62,119 | 0.71% | 2,033 | 32 | City |
| Gallatin | 2 | 54,405 | 44,825 | 3.65% | 1,559 | 35 | City |
| Portland | 3 | 13,760 | 13,213 | 0.8% | 909 | 15 | City |
| Westmoreland | 4 | 2,902 | 2,817 | 0.59% | 669 | 4 | Town |
| Castalian Springs | 5 | 636 | 397 | 0.79% | 109 | 6 | CDP |
| Cottontown | 6 | 340 | 356 | -0.29% | 97 | 4 | CDP |
| Bethpage | 7 | 273 | 481 | -0.36% | 206 | 1 | CDP |
| Mitchellville | 8 | 159 | 161 | -0.63% | 296 | 1 | City |
| Graball | 9 | 118 | 105 | -6.35% | 59 | 2 | CDP |
Hendersonville is the largest city in Sumner County, with a population of 64,404.
Graball is the smallest city in Sumner County, with a population of 118.
There are 9 cities in Sumner County, Tennessee.