19 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Oswego | 1 | 62,128 | 55,963 | 2.55% | 1,557 | 40 | Township |
| Oswego | 2 | 39,786 | 34,744 | 2.6% | 2,618 | 15 | Village |
| Bristol | 3 | 36,789 | 32,182 | 2.85% | 1,298 | 28 | Township |
| Yorkville | 4 | 27,041 | 21,765 | 4.06% | 1,352 | 20 | City |
| Montgomery | 5 | 22,336 | 20,440 | 1.73% | 2,325 | 10 | Village |
| Little Rock | 6 | 14,904 | 14,098 | 0.01% | 423 | 35 | Township |
| Plano | 7 | 12,869 | 11,908 | 1.51% | 1,433 | 9 | City |
| Na-Au-Say | 8 | 11,167 | 10,793 | 0.23% | 326 | 34 | Township |
| Kendall | 9 | 10,276 | 8,620 | 3.67% | 263 | 39 | Township |
| Montgomery | 10 | 2,464 | 2,456 | -0.36% | 68 | 36 | Township |
| Crystal Lawns | 11 | 1,842 | 1,943 | -0.11% | 2,795 | 1 | CDP |
| Fox | 12 | 1,658 | 1,633 | -0.12% | 46 | 36 | Township |
| Big Grove | 13 | 1,648 | 1,639 | -0.36% | 46 | 36 | Township |
| Newark | 14 | 981 | 976 | 0.1% | 873 | 1 | Village |
| Lisbon | 15 | 780 | 772 | -0.13% | 21 | 37 | Township |
| Millington | 16 | 625 | 618 | 0.16% | 883 | 1 | Village |
| Montgomery | 17 | 624 | 638 | -0.16% | 12 | 54 | Township |
| Millbrook | 18 | 402 | 406 | 0.5% | 11 | 37 | Township |
| Millbrook | 19 | 283 | 276 | 0.35% | 153 | 2 | Village |
Oswego is the largest city in Kendall County, with a population of 62,128.
Millbrook is the smallest city in Kendall County, with a population of 283.
There are 19 cities in Kendall County, Illinois.