39 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Peoria | 1 | 108,870 | 112,845 | -0.72% | 2,262 | 48.13 | City |
| Peoria City township | 2 | 94,939 | 97,612 | -0.3% | 2,370 | 40.06 | Township |
| Limestone township | 3 | 17,795 | 18,295 | -0.3% | 498 | 35.77 | Township |
| Medina township | 4 | 13,728 | 14,036 | -0.18% | 512 | 26.80 | Township |
| Kickapoo township | 5 | 8,101 | 8,273 | -0.16% | 252 | 32.16 | Township |
| Chillicothe township | 6 | 8,025 | 8,239 | -0.22% | 445 | 18.03 | Township |
| Chillicothe | 7 | 5,889 | 6,109 | -0.74% | 1,117 | 5.27 | City |
| Richwoods township | 8 | 5,701 | 5,895 | -0.42% | 1,913 | 2.98 | Township |
| Bartonville | 9 | 5,679 | 5,929 | -0.87% | 705 | 8.05 | Village |
| Peoria Heights | 10 | 5,649 | 5,893 | -0.86% | 2,266 | 2.49 | Village |
| Radnor township | 11 | 5,100 | 5,238 | -0.27% | 138 | 36.88 | Township |
| West Peoria | 12 | 4,085 | 4,252 | -0.8% | 1,940 | 2.11 | City |
| Elmwood township | 13 | 2,423 | 2,499 | -0.41% | 67 | 36.07 | Township |
| Timber township | 14 | 2,209 | 2,269 | -0.27% | 62 | 35.86 | Township |
| Elmwood | 15 | 1,976 | 2,055 | -0.8% | 1,415 | 1.40 | City |
| Bellevue | 16 | 1,813 | 1,878 | -0.71% | 815 | 2.22 | Village |
| Hollis township | 17 | 1,770 | 1,813 | -0.23% | 75 | 23.65 | Township |
| Jubilee township | 18 | 1,721 | 1,763 | -0.23% | 47 | 36.26 | Township |
| Rome township | 19 | 1,628 | 1,661 | -0.12% | 45 | 36.26 | Township |
| Princeville | 20 | 1,595 | 1,629 | -0.44% | 942 | 1.69 | Village |
| Rome | 21 | 1,572 | 1,394 | -0.69% | 817 | 1.92 | CDP |
| Dunlap | 22 | 1,552 | 1,611 | -0.77% | 557 | 2.78 | Village |
| Hallock township | 23 | 1,536 | 1,573 | -0.19% | 43 | 36.09 | Township |
| Lake Camelot | 24 | 1,535 | 1,631 | -0.65% | 882 | 1.74 | CDP |
| Princeville township | 25 | 1,510 | 1,535 | 0% | 42 | 36.37 | Township |
| Hanna City | 26 | 1,218 | 1,262 | -0.73% | 895 | 1.36 | Village |
| Rosefield township | 27 | 1,193 | 1,221 | -0.17% | 33 | 36.39 | Township |
| Brimfield township | 28 | 1,145 | 1,172 | -0.17% | 31 | 36.45 | Township |
| Akron township | 29 | 987 | 1,000 | 0% | 27 | 36.38 | Township |
| Trivoli township | 30 | 975 | 1,001 | -0.31% | 27 | 35.93 | Township |
| Glasford | 31 | 825 | 860 | -0.84% | 909 | 0.91 | Village |
| Brimfield | 32 | 751 | 776 | -0.66% | 815 | 0.92 | Village |
| Trivoli | 33 | 542 | 380 | 7.11% | 356 | 1.52 | CDP |
| Norwood | 34 | 424 | 439 | -0.7% | 1,381 | 0.31 | Village |
| Mossville | 35 | 275 | 263 | 7% | 220 | 1.25 | CDP |
| Smithville | 36 | 266 | 171 | 7.26% | 210 | 1.26 | CDP |
| Kingston Mines | 37 | 256 | 268 | -0.78% | 177 | 1.44 | Village |
| Mapleton | 38 | 245 | 257 | -0.81% | 277 | 0.89 | Village |
| West Peoria township | 39 | 13 | 0 | 30% | 6 | 2.16 | Township |
Peoria is the largest city in Peoria County, with a population of 108,870.
West Peoria township is the smallest city in Peoria County.
There are 39 cities in Peoria County, Illinois.