| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bethany | 1 | 2,962 | 2,910 | 0.2% | 667 | 4 | City |
| Ridgeway | 2 | 378 | 374 | 0% | 311 | 1 | City |
| Gilman City | 3 | 338 | 331 | 0.3% | 402 | 1 | City |
| Cainsville | 4 | 285 | 282 | 0% | 208 | 1 | City |
| Eagleville | 5 | 283 | 279 | 0% | 280 | 1 | Town |
| New Hampton | 6 | 228 | 224 | 0% | 415 | 1 | City |
| Blythedale | 7 | 212 | 209 | 0% | 691 | 0 | Village |
| Mount Moriah | 8 | 76 | 75 | 0% | 75 | 1 | Town |
| Irena | 9 | 13 | 13 | 0% | 15 | 1 | Village |
Bethany is the largest city in Harrison County, with a population of 2,962.
Irena is the smallest city in Harrison County, with a population of 13.
There are 9 cities in Harrison County, Missouri.