9 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bethany | 1 | 2,914 | 2,907 | 0.03% | 656 | 4 | City |
| Ridgeway | 2 | 378 | 374 | 0.27% | 311 | 1 | City |
| Gilman City | 3 | 329 | 329 | 0% | 391 | 1 | City |
| Cainsville | 4 | 282 | 282 | 0% | 206 | 1 | City |
| Eagleville | 5 | 280 | 280 | 0% | 277 | 1 | Town |
| New Hampton | 6 | 228 | 225 | 0.44% | 415 | 1 | City |
| Blythedale | 7 | 210 | 209 | 0% | 684 | 0 | Village |
| Mount Moriah | 8 | 76 | 76 | 0% | 75 | 1 | Town |
| Irena | 9 | 12 | 14 | 0% | 14 | 1 | Village |
Bethany is the largest city in Harrison County, with a population of 2,914.
Irena is the smallest city in Harrison County, with a population of 12.
There are 9 cities in Harrison County, Missouri.