40 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Aurora | 1 | 180,822 | 180,260 | 0.06% | 4,014 | 45 | City |
| Naperville | 2 | 154,046 | 149,434 | 0.6% | 3,934 | 39 | City |
| Downers Grove | 3 | 151,293 | 149,641 | 0.79% | 3,047 | 50 | Township |
| York | 4 | 129,479 | 128,246 | 0.81% | 3,694 | 35 | Township |
| Aurora | 5 | 127,085 | 126,777 | 0.38% | 3,679 | 35 | Township |
| Lisle | 6 | 121,319 | 118,886 | 1.03% | 3,430 | 35 | Township |
| Bloomingdale | 7 | 112,496 | 111,705 | 0.73% | 3,292 | 34 | Township |
| Naperville | 8 | 108,290 | 104,627 | 1.13% | 3,103 | 35 | Township |
| Addison | 9 | 88,794 | 88,160 | 0.79% | 2,825 | 31 | Township |
| Wayne | 10 | 64,752 | 64,305 | 0.88% | 1,829 | 35 | Township |
| Wheaton | 11 | 53,701 | 53,899 | -0.07% | 4,745 | 11 | City |
| Downers Grove | 12 | 50,644 | 50,182 | 0.18% | 3,456 | 15 | Village |
| Winfield | 13 | 47,992 | 45,884 | 0.73% | 1,380 | 35 | Township |
| Elmhurst | 14 | 46,203 | 45,727 | 0.21% | 4,522 | 10 | City |
| Lombard | 15 | 44,508 | 44,416 | 0.04% | 4,381 | 10 | Village |
| Bartlett | 16 | 40,641 | 41,023 | -0.19% | 2,576 | 16 | Village |
| Carol Stream | 17 | 39,505 | 39,760 | -0.13% | 4,330 | 9 | Village |
| Addison | 18 | 35,752 | 35,631 | 0.07% | 3,638 | 10 | Village |
| Woodridge | 19 | 34,099 | 34,116 | -0.01% | 3,540 | 10 | Village |
| Glendale Heights | 20 | 32,807 | 33,100 | -0.18% | 6,082 | 5 | Village |
| Glen Ellyn | 21 | 28,854 | 28,941 | -0.06% | 4,187 | 7 | Village |
| West Chicago | 22 | 25,445 | 25,563 | -0.09% | 1,653 | 15 | City |
| Westmont | 23 | 24,282 | 24,412 | -0.11% | 4,842 | 5 | Village |
| Lisle | 24 | 23,519 | 23,664 | -0.12% | 3,411 | 7 | Village |
| Roselle | 25 | 22,858 | 22,923 | -0.06% | 4,133 | 6 | Village |
| Bloomingdale | 26 | 22,689 | 22,353 | 0.3% | 3,353 | 7 | Village |
| Darien | 27 | 22,019 | 21,998 | 0.02% | 3,570 | 6 | City |
| Villa Park | 28 | 21,973 | 22,206 | -0.21% | 4,653 | 5 | Village |
| Bensenville | 29 | 18,593 | 18,772 | -0.19% | 3,361 | 6 | Village |
| Hinsdale | 30 | 17,655 | 17,368 | 0.32% | 3,819 | 5 | Village |
| Warrenville | 31 | 15,651 | 13,631 | 2.65% | 2,865 | 5 | City |
| Wood Dale | 32 | 13,970 | 14,034 | -0.09% | 2,917 | 5 | City |
| Winfield | 33 | 10,296 | 9,810 | 0.95% | 3,327 | 3 | Village |
| Itasca | 34 | 9,497 | 9,541 | -0.09% | 1,891 | 5 | Village |
| Willowbrook | 35 | 9,168 | 9,221 | -0.12% | 3,560 | 3 | Village |
| Clarendon Hills | 36 | 8,706 | 8,689 | 0.03% | 4,810 | 2 | Village |
| Oak Brook | 37 | 8,198 | 8,148 | 0.12% | 1,028 | 8 | Village |
| Willowbrook | 38 | 2,655 | 2,062 | 1.49% | 1,810 | 1 | CDP |
| Wayne | 39 | 2,286 | 2,280 | 0.04% | 399 | 6 | Village |
| Chicago | 40 | 0 | 0 | 0.00 | 3 | City |
Aurora is the largest city in DuPage County, with a population of 180,822.
Chicago is the smallest city in DuPage County, with a population of 0.
There are 40 cities in DuPage County, Illinois.