9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Hendersonville | 1 | 64,617 | 62,119 | 0.78% | 2,040 | 31.68 | City |
| Gallatin | 2 | 54,040 | 44,827 | 3.53% | 1,549 | 34.89 | City |
| Portland | 3 | 13,824 | 13,209 | 0.9% | 913 | 15.14 | City |
| Westmoreland | 4 | 2,822 | 2,727 | 0.68% | 650 | 4.34 | Town |
| Castalian Springs | 5 | 636 | 397 | 0.79% | 109 | 5.82 | CDP |
| Cottontown | 6 | 340 | 356 | -0.29% | 97 | 3.51 | CDP |
| Bethpage | 7 | 273 | 481 | -0.36% | 206 | 1.33 | CDP |
| Mitchellville | 8 | 156 | 161 | -0.64% | 291 | 0.54 | City |
| Graball | 9 | 118 | 105 | -6.35% | 59 | 2.01 | CDP |
Hendersonville is the largest city in Sumner County, with a population of 64,617.
Graball is the smallest city in Sumner County.
There are 9 cities in Sumner County, Tennessee.