7 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Oswego | 1 | 40,795 | 34,744 | 2.54% | 2,516 | 16 | Village |
| Yorkville | 2 | 28,096 | 21,765 | 3.9% | 1,375 | 20 | City |
| Montgomery | 3 | 22,715 | 20,440 | 1.7% | 2,267 | 10 | Village |
| Plano | 4 | 13,061 | 11,908 | 1.49% | 1,455 | 9 | City |
| Newark | 5 | 982 | 976 | 0.1% | 874 | 1 | Village |
| Millington | 6 | 627 | 618 | 0.32% | 886 | 1 | Village |
| Millbrook | 7 | 285 | 276 | 0.71% | 154 | 2 | Village |
Oswego is the largest city in Kendall County, with a population of 40,795.
Millbrook is the smallest city in Kendall County, with a population of 285.
There are 7 cities in Kendall County, Illinois.