18 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Oswego | 1 | 63,675 | 55,963 | 2.49% | 1,595 | 40 | Township |
| Oswego | 2 | 40,795 | 34,744 | 2.54% | 2,516 | 16 | Village |
| Bristol | 3 | 37,807 | 32,182 | 2.77% | 1,334 | 28 | Township |
| Yorkville | 4 | 28,096 | 21,765 | 3.9% | 1,375 | 20 | City |
| Montgomery | 5 | 22,715 | 20,440 | 1.7% | 2,267 | 10 | Village |
| Little Rock | 6 | 14,906 | 14,098 | 0.01% | 423 | 35 | Township |
| Plano | 7 | 13,061 | 11,908 | 1.49% | 1,455 | 9 | City |
| Na-Au-Say | 8 | 11,193 | 10,793 | 0.23% | 327 | 34 | Township |
| Kendall | 9 | 10,640 | 8,620 | 3.54% | 272 | 39 | Township |
| Montgomery | 10 | 2,455 | 2,456 | -0.37% | 68 | 36 | Township |
| Fox | 11 | 1,656 | 1,633 | -0.12% | 46 | 36 | Township |
| Big Grove | 12 | 1,642 | 1,639 | -0.36% | 46 | 36 | Township |
| Newark | 13 | 982 | 976 | 0.1% | 874 | 1 | Village |
| Lisbon | 14 | 779 | 772 | -0.13% | 21 | 37 | Township |
| Millington | 15 | 627 | 618 | 0.32% | 886 | 1 | Village |
| Montgomery | 16 | 623 | 638 | -0.16% | 12 | 54 | Township |
| Millbrook | 17 | 404 | 406 | 0.5% | 11 | 37 | Township |
| Millbrook | 18 | 285 | 276 | 0.71% | 154 | 2 | Village |
Oswego is the largest city in Kendall County, with a population of 63,675.
Millbrook is the smallest city in Kendall County, with a population of 285.
There are 18 cities in Kendall County, Illinois.