19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Oswego township | 1 | 61,055 | 55,959 | 1.93% | 1,530 | 39.91 | Township |
| Oswego | 2 | 38,640 | 34,724 | 2.07% | 2,542 | 15.20 | Village |
| Bristol township | 3 | 36,285 | 32,177 | 2.13% | 1,280 | 28.35 | Township |
| Yorkville | 4 | 26,701 | 21,681 | 3.91% | 1,335 | 20 | City |
| Montgomery | 5 | 22,968 | 20,435 | 2.26% | 2,391 | 9.61 | Village |
| Little Rock township | 6 | 15,291 | 14,107 | 1.26% | 434 | 35.23 | Township |
| Plano | 7 | 13,186 | 11,910 | 1.97% | 1,469 | 8.98 | City |
| Na-Au-Say township | 8 | 11,278 | 10,789 | 0.73% | 329 | 34.24 | Township |
| Kendall township | 9 | 10,062 | 8,619 | 2.59% | 258 | 39.07 | Township |
| Montgomery township | 10 | 2,497 | 2,445 | 0.6% | 69 | 36.19 | Township |
| Crystal Lawns | 11 | 1,842 | 1,943 | -0.11% | 2,795 | 0.66 | CDP |
| Fox township | 12 | 1,679 | 1,637 | 0.42% | 46 | 36.17 | Township |
| Big Grove township | 13 | 1,671 | 1,638 | 0.36% | 47 | 35.72 | Township |
| Newark | 14 | 992 | 976 | 0.3% | 883 | 1.12 | Village |
| Lisbon township | 15 | 785 | 773 | 0.13% | 21 | 36.59 | Township |
| Millington | 16 | 623 | 618 | 0.16% | 880 | 0.71 | Village |
| Montgomery township | 17 | 612 | 637 | -0.97% | 11 | 54.03 | Township |
| Millbrook township | 18 | 391 | 407 | -0.76% | 11 | 36.53 | Township |
| Millbrook | 19 | 282 | 277 | 0.36% | 153 | 1.85 | Village |
Oswego township is the largest city in Kendall County, with a population of 61,055.
Millbrook is the smallest city in Kendall County.
There are 19 cities in Kendall County, Illinois.