35 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Dixon township | 1 | 16,876 | 17,341 | -0.81% | 583 | 28.95 | Township |
| Dixon | 2 | 14,989 | 15,256 | -0.35% | 1,768 | 8.48 | City |
| Amboy township | 3 | 2,717 | 2,819 | -1.06% | 77 | 35.31 | Township |
| Amboy | 4 | 2,210 | 2,275 | -0.58% | 356 | 6.21 | City |
| Franklin Grove township | 5 | 1,183 | 1,227 | -1% | 44 | 26.80 | Township |
| Ashton township | 6 | 1,117 | 1,160 | -0.98% | 63 | 17.85 | Township |
| South Dixon township | 7 | 951 | 974 | -0.63% | 32 | 29.66 | Township |
| Ashton | 8 | 934 | 966 | -0.64% | 1,295 | 0.72 | Village |
| Franklin Grove | 9 | 867 | 897 | -0.69% | 2,084 | 0.42 | Village |
| Paw Paw | 10 | 800 | 827 | -0.62% | 1,336 | 0.60 | Village |
| Nelson township | 11 | 745 | 762 | -0.67% | 33 | 22.50 | Township |
| Lost Nation | 12 | 733 | 570 | 0.27% | 300 | 2.44 | CDP |
| Brooklyn township | 13 | 678 | 702 | -1.02% | 19 | 36.22 | Township |
| Sublette township | 14 | 672 | 693 | -0.88% | 18 | 36.52 | Township |
| Willow Creek township | 15 | 616 | 637 | -0.96% | 18 | 35.11 | Township |
| Como | 16 | 610 | 525 | 0.49% | 572 | 1.07 | CDP |
| Lee Center township | 17 | 531 | 546 | -0.93% | 15 | 36.28 | Township |
| Alto township | 18 | 509 | 526 | -0.97% | 15 | 34.91 | Township |
| Nachusa township | 19 | 436 | 450 | -0.91% | 15 | 28.91 | Township |
| Sublette | 20 | 370 | 379 | -0.54% | 925 | 0.40 | Village |
| Harmon township | 21 | 337 | 348 | -0.88% | 9 | 35.86 | Township |
| Paw Paw township | 22 | 306 | 314 | -0.65% | 8 | 37.59 | Township |
| Lee | 23 | 301 | 313 | -0.66% | 1,520 | 0.20 | Village |
| Grand Detour | 24 | 270 | 351 | -3.91% | 231 | 1.17 | CDP |
| Compton | 25 | 263 | 270 | -0.38% | 1,594 | 0.17 | Village |
| Lee township | 26 | 253 | 254 | -0.78% | 7 | 37.64 | Township |
| May township | 27 | 250 | 257 | -0.79% | 7 | 35.45 | Township |
| East Grove township | 28 | 242 | 249 | -0.82% | 7 | 35.57 | Township |
| Steward | 29 | 222 | 227 | -0.45% | 1,682 | 0.13 | Village |
| Lee township | 30 | 205 | 213 | -0.97% | 6 | 37.17 | Township |
| Nachusa | 31 | 172 | 122 | 6.83% | 225 | 0.76 | CDP |
| Coleta | 32 | 158 | 163 | -0.63% | 427 | 0.37 | Village |
| West Brooklyn | 33 | 127 | 131 | -0.78% | 1,351 | 0.09 | Village |
| Nelson | 34 | 122 | 126 | -0.81% | 342 | 0.36 | Village |
| Harmon | 35 | 115 | 119 | -0.86% | 528 | 0.22 | Village |
Dixon township is the largest city in Lee County, with a population of 16,876.
Harmon is the smallest city in Lee County.
There are 35 cities in Lee County, Illinois.