10 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Rockford | 1 | 146,881 | 148,696 | -0.21% | 2,246 | 65 | City |
| Loves Park | 2 | 23,754 | 23,400 | 0.25% | 1,455 | 16 | City |
| Machesney Park | 3 | 22,792 | 22,933 | -0.1% | 1,797 | 13 | Village |
| Roscoe | 4 | 10,990 | 10,962 | 0.05% | 1,071 | 10 | Village |
| South Beloit | 5 | 7,983 | 7,982 | 0% | 1,299 | 6 | City |
| Rockton | 6 | 7,862 | 7,859 | 0.01% | 1,146 | 7 | Village |
| Winnebago | 7 | 2,898 | 2,924 | -0.14% | 1,498 | 2 | Village |
| Cherry Valley | 8 | 2,886 | 2,892 | -0.03% | 343 | 8 | Village |
| Pecatonica | 9 | 2,047 | 2,080 | -0.24% | 1,595 | 1 | Village |
| Durand | 10 | 1,380 | 1,389 | -0.07% | 1,502 | 1 | Village |
Rockford is the largest city in Winnebago County, with a population of 146,881.
Durand is the smallest city in Winnebago County, with a population of 1,380.
There are 10 cities in Winnebago County, Illinois.