15 cities
| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Peoria | 1 | 111,073 | 112,942 | -0.28% | 2,308 | 48 | City |
| Chillicothe | 2 | 6,022 | 6,111 | -0.25% | 1,142 | 5 | City |
| Bartonville | 3 | 5,789 | 5,929 | -0.4% | 719 | 8 | Village |
| Peoria Heights | 4 | 5,756 | 5,894 | -0.4% | 2,309 | 2 | Village |
| West Peoria | 5 | 4,177 | 4,257 | -0.31% | 1,983 | 2 | City |
| Elmwood | 6 | 2,026 | 2,070 | -0.34% | 1,451 | 1 | City |
| Bellevue | 7 | 1,917 | 1,874 | 0.37% | 862 | 2 | Village |
| Princeville | 8 | 1,717 | 1,723 | -0.06% | 1,014 | 2 | Village |
| Dunlap | 9 | 1,588 | 1,612 | -0.25% | 570 | 3 | Village |
| Hanna City | 10 | 1,240 | 1,263 | -0.32% | 911 | 1 | Village |
| Glasford | 11 | 843 | 860 | -0.35% | 928 | 1 | Village |
| Brimfield | 12 | 766 | 777 | -0.26% | 832 | 1 | Village |
| Norwood | 13 | 431 | 437 | -0.23% | 1,404 | 0 | Village |
| Kingston Mines | 14 | 265 | 271 | -0.38% | 184 | 1 | Village |
| Mapleton | 15 | 251 | 257 | -0.4% | 284 | 1 | Village |
Peoria is the largest city in Peoria County, with a population of 111,073.
Mapleton is the smallest city in Peoria County, with a population of 251.
There are 15 cities in Peoria County, Illinois.