24 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Guilford township | 1 | 37,246 | 34,006 | 1.94% | 1,045 | 35.64 | Township |
| Lawrenceburg township | 2 | 11,388 | 11,274 | 0.38% | 474 | 24.01 | Township |
| Miller township | 3 | 10,185 | 9,944 | 0.66% | 397 | 25.64 | Township |
| Bright | 4 | 5,899 | 5,801 | 0.22% | 470 | 12.54 | CDP |
| Hidden Valley | 5 | 5,603 | 5,075 | 0.25% | 1,321 | 4.24 | CDP |
| Lawrenceburg | 6 | 5,232 | 5,137 | 0.36% | 990 | 5.29 | City |
| Center township | 7 | 5,165 | 5,059 | 0.6% | 480 | 10.76 | Township |
| Greendale | 8 | 4,536 | 4,606 | -0.31% | 801 | 5.66 | City |
| Logan township | 9 | 3,976 | 3,872 | 0.71% | 223 | 17.82 | Township |
| Aurora | 10 | 3,525 | 3,482 | 0.26% | 1,071 | 3.29 | City |
| Harrison township | 11 | 3,455 | 3,376 | 0.64% | 203 | 16.99 | Township |
| Manchester township | 12 | 3,374 | 3,292 | 0.69% | 74 | 45.48 | Township |
| Sparta township | 13 | 3,001 | 2,901 | 0.87% | 102 | 29.44 | Township |
| Clay township | 14 | 2,905 | 2,838 | 0.62% | 115 | 25.25 | Township |
| Kelso township | 15 | 2,529 | 2,477 | 0.6% | 99 | 25.55 | Township |
| Jackson township | 16 | 1,776 | 1,730 | 0.74% | 72 | 24.67 | Township |
| Dillsboro | 17 | 1,394 | 1,366 | 0.43% | 1,030 | 1.35 | Town |
| Hogan township | 18 | 1,164 | 1,138 | 0.61% | 76 | 15.38 | Township |
| York township | 19 | 1,150 | 1,123 | 0.7% | 62 | 18.59 | Township |
| Moores Hill | 20 | 695 | 675 | 0.58% | 1,616 | 0.43 | Town |
| St. Leon | 21 | 667 | 662 | 0.15% | 98 | 6.83 | Town |
| West Harrison | 22 | 336 | 331 | 0.3% | 1,520 | 0.22 | Town |
| Caesar Creek township | 23 | 274 | 266 | 0.74% | 23 | 11.93 | Township |
| Mount Carmel | 24 | 79 | 78 | 0% | 1,795 | 0.04 | Town |
Guilford township is the largest city in Dearborn County, with a population of 37,246.
Mount Carmel is the smallest city in Dearborn County.
There are 24 cities in Dearborn County, Indiana.