9 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Ashland | 1 | 20,935 | 21,627 | -0.62% | 1,950 | 11 | City |
| Ashland | 2 | 20,935 | 21,589 | -0.62% | 1,950 | 11 | City |
| Westwood | 3 | 4,540 | 4,654 | -0.31% | 1,215 | 4 | CDP |
| Catlettsburg | 4 | 1,715 | 1,767 | -0.58% | 1,286 | 1 | City |
| Catlettsburg | 5 | 1,715 | 1,764 | -0.58% | 1,286 | 1 | City |
| Cannonsburg | 6 | 1,076 | 676 | 1.41% | 617 | 2 | CDP |
| Ironville | 7 | 919 | 1,028 | 7.11% | 1,183 | 1 | CDP |
| Bellefonte | 8 | 875 | 914 | -0.91% | 993 | 1 | City |
| Bellefonte | 9 | 875 | 912 | -0.91% | 993 | 1 | City |
Ashland is the largest city in Boyd County, with a population of 20,935.
Bellefonte is the smallest city in Boyd County, with a population of 875.
There are 9 cities in Boyd County, Kentucky.