19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Harrison | 1 | 13,706 | 13,476 | 0.49% | 135 | 101 | Township |
| Jackson | 2 | 6,074 | 5,981 | 0.46% | 168 | 36 | Township |
| Morgan | 3 | 4,118 | 4,019 | 0.64% | 115 | 36 | Township |
| Corydon | 4 | 3,171 | 3,163 | 0.06% | 1,919 | 2 | Town |
| Posey | 5 | 2,913 | 2,841 | 0.66% | 73 | 40 | Township |
| Blue River | 6 | 2,044 | 1,992 | 0.74% | 53 | 38 | Township |
| Palmyra | 7 | 1,512 | 1,487 | 0.8% | 40 | 37 | Township |
| Boone | 8 | 1,319 | 1,305 | 0.38% | 28 | 47 | Township |
| Heth | 9 | 1,207 | 1,166 | 0.84% | 36 | 34 | Township |
| Lanesville | 10 | 944 | 936 | 0.21% | 1,003 | 1 | Town |
| Palmyra | 11 | 904 | 898 | 0.11% | 756 | 1 | Town |
| Taylor | 12 | 782 | 770 | 0.51% | 28 | 28 | Township |
| New Salisbury | 13 | 462 | 613 | -2.12% | 234 | 2 | CDP |
| Elizabeth | 14 | 202 | 201 | 0% | 774 | 0 | Town |
| Crandall | 15 | 139 | 136 | 0.72% | 1,337 | 0 | Town |
| New Middletown | 16 | 92 | 91 | 0% | 2,629 | 0 | Town |
| Laconia | 17 | 71 | 70 | 0% | 1,392 | 0 | Town |
| Mauckport | 18 | 46 | 45 | 0% | 230 | 0 | Town |
| New Amsterdam | 19 | 12 | 12 | 0% | 158 | 0 | Town |
Harrison is the largest city in Harrison County, with a population of 13,706.
New Amsterdam is the smallest city in Harrison County, with a population of 12.
There are 19 cities in Harrison County, Indiana.