| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Kankakee | 1 | 23,267 | 23,996 | -0.57% | 1,536 | 15 | City |
| Bourbonnais | 2 | 17,559 | 18,097 | -0.56% | 1,886 | 9 | Village |
| Bradley | 3 | 15,184 | 15,386 | -0.2% | 2,087 | 7 | Village |
| Manteno | 4 | 9,206 | 9,180 | 0.05% | 1,720 | 5 | Village |
| Momence | 5 | 3,139 | 3,249 | -0.6% | 1,988 | 2 | City |
| Limestone | 6 | 1,511 | 1,552 | -0.46% | 543 | 3 | Village |
| Herscher | 7 | 1,479 | 1,521 | -0.47% | 816 | 2 | Village |
| Grant Park | 8 | 1,269 | 1,285 | -0.16% | 372 | 3 | Village |
| St. Anne | 9 | 1,114 | 1,159 | -0.71% | 1,342 | 1 | Village |
| Essex | 10 | 851 | 842 | 0.24% | 366 | 2 | Village |
| Hopkins Park | 11 | 649 | 607 | 0.62% | 156 | 4 | Village |
| Aroma Park | 12 | 644 | 651 | -0.46% | 342 | 2 | Village |
| Bonfield | 13 | 335 | 348 | -0.89% | 681 | 0 | Village |
| Buckingham | 14 | 235 | 241 | -0.42% | 936 | 0 | Village |
| Sammons Point | 15 | 222 | 230 | -0.45% | 120 | 2 | Village |
| Reddick | 16 | 187 | 192 | -0.53% | 782 | 0 | Village |
| Irwin | 17 | 62 | 65 | -1.59% | 1,378 | 0 | Village |
| Union Hill | 18 | 48 | 52 | -2.04% | 738 | 0 | Village |
Kankakee is the largest city in Kankakee County, with a population of 23,267.
Union Hill is the smallest city in Kankakee County, with a population of 48.
There are 18 cities in Kankakee County, Illinois.