| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Peoria | 1 | 110,431 | 112,895 | -0.44% | 2,295 | 48 | City |
| Chillicothe | 2 | 6,010 | 6,109 | -0.38% | 1,140 | 5 | City |
| Bartonville | 3 | 5,774 | 5,930 | -0.52% | 717 | 8 | Village |
| Peoria Heights | 4 | 5,737 | 5,893 | -0.52% | 2,301 | 2 | Village |
| West Peoria | 5 | 4,167 | 4,266 | -0.48% | 1,979 | 2 | City |
| Elmwood | 6 | 2,019 | 2,070 | -0.54% | 1,446 | 1 | City |
| Bellevue | 7 | 1,892 | 1,873 | 0.21% | 851 | 2 | Village |
| Princeville | 8 | 1,709 | 1,728 | -0.23% | 1,009 | 2 | Village |
| Dunlap | 9 | 1,582 | 1,609 | -0.38% | 568 | 3 | Village |
| Hanna City | 10 | 1,232 | 1,259 | -0.48% | 905 | 1 | Village |
| Glasford | 11 | 837 | 860 | -0.59% | 922 | 1 | Village |
| Brimfield | 12 | 761 | 775 | -0.39% | 826 | 1 | Village |
| Norwood | 13 | 429 | 437 | -0.46% | 1,397 | 0 | Village |
| Kingston Mines | 14 | 257 | 265 | -0.77% | 178 | 1 | Village |
| Mapleton | 15 | 249 | 257 | -0.8% | 281 | 1 | Village |
Peoria is the largest city in Peoria County, with a population of 110,431.
Mapleton is the smallest city in Peoria County, with a population of 249.
There are 15 cities in Peoria County, Illinois.