20 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Indianapolis | 1 | 874,037 | 887,177 | -0.3% | 2,421 | 361.02 | Township |
| Fishers | 2 | 107,169 | 99,481 | 1.46% | 2,973 | 36.05 | City |
| Carmel | 3 | 103,890 | 99,905 | 0.77% | 2,116 | 49.09 | City |
| Clay township | 4 | 101,948 | 99,239 | 0.16% | 2,075 | 49.12 | Township |
| Fall Creek township | 5 | 77,288 | 71,203 | 1.8% | 2,293 | 33.71 | Township |
| Noblesville | 6 | 76,425 | 70,152 | 1.67% | 2,195 | 34.82 | City |
| Noblesville township | 7 | 68,599 | 64,340 | 0.89% | 1,465 | 46.83 | Township |
| Westfield | 8 | 64,900 | 47,015 | 5.83% | 1,990 | 32.61 | City |
| Delaware township | 9 | 37,790 | 34,880 | 1.75% | 2,482 | 15.22 | Township |
| McCordsville | 10 | 12,869 | 8,878 | 6.61% | 1,552 | 8.29 | Town |
| Jackson township | 11 | 11,544 | 10,882 | 0.79% | 211 | 54.83 | Township |
| Wayne township | 12 | 11,516 | 10,965 | 0.57% | 328 | 35.09 | Township |
| Cicero township | 13 | 7,941 | 8,075 | -0.44% | 118 | 67.50 | Township |
| Cicero | 14 | 5,836 | 5,320 | 1.8% | 3,583 | 1.63 | Town |
| Adams township | 15 | 5,519 | 5,217 | 0.97% | 114 | 48.27 | Township |
| Sheridan | 16 | 3,527 | 3,111 | 2.41% | 1,400 | 2.52 | Town |
| White River township | 17 | 2,263 | 2,413 | -1.86% | 41 | 55.60 | Township |
| Arcadia | 18 | 1,448 | 1,513 | -0.89% | 2,628 | 0.55 | Town |
| Atlanta | 19 | 762 | 721 | 1.06% | 2,435 | 0.31 | Town |
| Williams Creek | 20 | 423 | 428 | -0.24% | 1,274 | 0.33 | Town |
Indianapolis is the largest city in Hamilton County, with a population of 874,037.
Williams Creek is the smallest city in Hamilton County.
There are 20 cities in Hamilton County, Indiana.