34 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Richland | 1 | 15,393 | 15,093 | 0.55% | 434 | 35 | Township |
| Troy | 2 | 12,022 | 11,945 | 0.11% | 279 | 43 | Township |
| Richland | 3 | 5,264 | 5,043 | 1.39% | 190 | 28 | Township |
| Ohio | 4 | 4,949 | 4,849 | 0.69% | 73 | 68 | Township |
| Richland | 5 | 4,722 | 4,673 | 0.17% | 110 | 43 | Township |
| Richland | 6 | 3,914 | 3,980 | 0.38% | 144 | 27 | Township |
| Troy | 7 | 3,830 | 3,726 | 0.9% | 87 | 44 | Township |
| Carter | 8 | 3,281 | 3,234 | 0.61% | 92 | 36 | Township |
| Clay | 9 | 2,982 | 2,870 | 1.33% | 82 | 36 | Township |
| Santa Claus | 10 | 2,674 | 2,589 | 0.64% | 412 | 6 | Town |
| Luce | 11 | 2,473 | 2,386 | 0.9% | 47 | 53 | Township |
| Rockport | 12 | 1,988 | 1,991 | -0.05% | 1,199 | 2 | City |
| Harrison | 13 | 1,958 | 1,913 | 0.72% | 36 | 55 | Township |
| Richland | 14 | 1,797 | 1,778 | 0.06% | 48 | 37 | Township |
| Dale | 15 | 1,529 | 1,541 | -0.2% | 633 | 2 | Town |
| Richland | 16 | 1,287 | 1,257 | 0.23% | 55 | 23 | Township |
| Grass | 17 | 1,144 | 1,119 | 0.7% | 25 | 45 | Township |
| Huff | 18 | 1,083 | 1,050 | 1.03% | 26 | 42 | Township |
| Richland | 19 | 1,078 | 1,085 | 0.65% | 27 | 40 | Township |
| Richland | 20 | 1,047 | 1,096 | -1.78% | 28 | 37 | Township |
| Richland | 21 | 894 | 895 | 0.11% | 38 | 24 | Township |
| Jackson | 22 | 839 | 804 | 0.96% | 41 | 20 | Township |
| Richland | 23 | 835 | 828 | 0.72% | 16 | 52 | Township |
| St. Meinrad | 24 | 806 | 707 | 0.88% | 479 | 2 | CDP |
| Grandview | 25 | 707 | 696 | 0.28% | 737 | 1 | Town |
| Hatfield | 26 | 568 | 772 | -2.74% | 485 | 1 | CDP |
| Richland | 27 | 564 | 551 | 1.08% | 16 | 36 | Township |
| Chrisney | 28 | 476 | 466 | 0.42% | 674 | 1 | Town |
| Richland | 29 | 418 | 408 | 0.48% | 812 | 1 | Town |
| Richland | 30 | 407 | 404 | 0% | 26 | 16 | Township |
| Troy | 31 | 372 | 346 | 1.36% | 329 | 1 | Town |
| Richland | 32 | 328 | 330 | -0.61% | 12 | 29 | Township |
| Troy | 33 | 324 | 314 | 0.62% | 22 | 15 | Township |
| Gentryville | 34 | 261 | 244 | 1.16% | 662 | 0 | Town |
Richland is the largest city in Spencer County, with a population of 15,393.
Gentryville is the smallest city in Spencer County, with a population of 261.
There are 34 cities in Spencer County, Indiana.