| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Rockford | 1 | 146,961 | 148,789 | -0.29% | 2,247 | 65 | City |
| Loves Park | 2 | 23,758 | 23,431 | 0.19% | 1,455 | 16 | City |
| Machesney Park | 3 | 22,768 | 22,932 | -0.16% | 1,795 | 13 | Village |
| Roscoe | 4 | 11,031 | 10,999 | -0.03% | 1,075 | 10 | Village |
| South Beloit | 5 | 7,993 | 7,975 | -0.04% | 1,301 | 6 | City |
| Rockton | 6 | 7,864 | 7,862 | -0.08% | 1,146 | 7 | Village |
| Winnebago | 7 | 2,896 | 2,925 | -0.24% | 1,497 | 2 | Village |
| Cherry Valley | 8 | 2,885 | 2,882 | -0.07% | 343 | 8 | Village |
| Pecatonica | 9 | 2,045 | 2,080 | -0.34% | 1,594 | 1 | Village |
| Durand | 10 | 1,378 | 1,382 | -0.14% | 1,499 | 1 | Village |
Rockford is the largest city in Winnebago County, with a population of 146,961.
Durand is the smallest city in Winnebago County, with a population of 1,378.
There are 10 cities in Winnebago County, Illinois.