23 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Bethany | 1 | 3,293 | 3,313 | -0.36% | 92 | 36 | Township |
| Bethany | 2 | 2,914 | 2,907 | 0.03% | 656 | 4 | City |
| Colfax | 3 | 577 | 580 | -0.52% | 14 | 43 | Township |
| White Oak | 4 | 456 | 452 | 0% | 13 | 36 | Township |
| Sugar Creek | 5 | 450 | 449 | -0.22% | 15 | 30 | Township |
| Grant | 6 | 380 | 381 | -0.26% | 11 | 34 | Township |
| Ridgeway | 7 | 378 | 374 | 0.27% | 311 | 1 | City |
| Marion | 8 | 362 | 363 | -0.28% | 10 | 35 | Township |
| Gilman City | 9 | 329 | 329 | 0% | 391 | 1 | City |
| Jefferson | 10 | 326 | 328 | -0.31% | 9 | 36 | Township |
| Cainsville | 11 | 282 | 282 | 0% | 206 | 1 | City |
| Eagleville | 12 | 280 | 280 | 0% | 277 | 1 | Town |
| New Hampton | 13 | 228 | 225 | 0.44% | 415 | 1 | City |
| Dallas | 14 | 214 | 215 | -0.47% | 6 | 36 | Township |
| Blythedale | 15 | 210 | 209 | 0% | 684 | 0 | Village |
| Sherman | 16 | 190 | 191 | -0.52% | 5 | 35 | Township |
| Trail Creek | 17 | 190 | 191 | -0.52% | 5 | 36 | Township |
| Cypress | 18 | 160 | 161 | -0.62% | 5 | 30 | Township |
| Adams | 19 | 133 | 132 | 0% | 4 | 30 | Township |
| Fox Creek | 20 | 101 | 100 | 0% | 3 | 36 | Township |
| Mount Moriah | 21 | 76 | 76 | 0% | 75 | 1 | Town |
| Clay | 22 | 63 | 65 | -1.56% | 1 | 44 | Township |
| Irena | 23 | 12 | 14 | 0% | 14 | 1 | Village |
Bethany is the largest city in Harrison County, with a population of 3,293.
Irena is the smallest city in Harrison County, with a population of 12.
There are 23 cities in Harrison County, Missouri.