40 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Aurora | 1 | 175,795 | 180,215 | -0.5% | 3,902 | 45 | City |
| Naperville | 2 | 150,795 | 149,419 | 0.18% | 3,851 | 39 | City |
| Downers Grove | 3 | 148,333 | 149,632 | 0.18% | 2,987 | 50 | Township |
| York | 4 | 126,058 | 128,191 | -0.14% | 3,597 | 35 | Township |
| Aurora | 5 | 125,493 | 126,772 | -0.08% | 3,633 | 35 | Township |
| Lisle | 6 | 117,936 | 118,883 | -0.01% | 3,334 | 35 | Township |
| Bloomingdale | 7 | 109,645 | 111,713 | -0.18% | 3,208 | 34 | Township |
| Naperville | 8 | 104,223 | 104,607 | 0.04% | 2,987 | 35 | Township |
| Addison | 9 | 86,524 | 88,155 | -0.13% | 2,753 | 31 | Township |
| Wayne | 10 | 62,857 | 64,301 | -0.23% | 1,775 | 35 | Township |
| Wheaton | 11 | 52,354 | 53,814 | -0.55% | 4,626 | 11 | City |
| Downers Grove | 12 | 49,425 | 50,127 | -0.28% | 3,373 | 15 | Village |
| Winfield | 13 | 47,179 | 45,874 | 0.24% | 1,357 | 35 | Township |
| Elmhurst | 14 | 45,074 | 45,728 | -0.29% | 4,411 | 10 | City |
| Lombard | 15 | 43,369 | 44,393 | -0.47% | 4,269 | 10 | Village |
| Bartlett | 16 | 39,308 | 41,018 | -0.86% | 2,491 | 16 | Village |
| Carol Stream | 17 | 38,433 | 39,765 | -0.69% | 4,212 | 9 | Village |
| Addison | 18 | 34,852 | 35,639 | -0.45% | 3,546 | 10 | Village |
| Woodridge | 19 | 33,203 | 34,110 | -0.54% | 3,447 | 10 | Village |
| Glendale Heights | 20 | 31,946 | 33,103 | -0.72% | 5,923 | 5 | Village |
| Glen Ellyn | 21 | 27,999 | 28,869 | -0.62% | 4,063 | 7 | Village |
| West Chicago | 22 | 24,817 | 25,564 | -0.6% | 1,612 | 15 | City |
| Westmont | 23 | 23,632 | 24,384 | -0.63% | 4,712 | 5 | Village |
| Lisle | 24 | 22,922 | 23,671 | -0.65% | 3,324 | 7 | Village |
| Bloomingdale | 25 | 22,260 | 22,354 | -0.09% | 3,290 | 7 | Village |
| Roselle | 26 | 22,232 | 22,921 | -0.62% | 4,020 | 6 | Village |
| Darien | 27 | 21,497 | 21,999 | -0.46% | 3,485 | 6 | City |
| Villa Park | 28 | 21,407 | 22,206 | -0.74% | 4,533 | 5 | Village |
| Bensenville | 29 | 18,083 | 18,755 | -0.74% | 3,269 | 6 | Village |
| Hinsdale | 30 | 17,246 | 17,373 | -0.14% | 3,730 | 5 | Village |
| Warrenville | 31 | 15,959 | 13,629 | 3.01% | 2,922 | 5 | City |
| Wood Dale | 32 | 13,602 | 14,032 | -0.63% | 2,840 | 5 | City |
| Winfield | 33 | 10,214 | 9,813 | 0.79% | 3,300 | 3 | Village |
| Itasca | 34 | 9,228 | 9,522 | -0.64% | 1,838 | 5 | Village |
| Willowbrook | 35 | 8,923 | 9,210 | -0.63% | 3,465 | 3 | Village |
| Clarendon Hills | 36 | 8,477 | 8,689 | -0.49% | 4,683 | 2 | Village |
| Oak Brook | 37 | 7,979 | 8,153 | -0.44% | 1,000 | 8 | Village |
| Willowbrook | 38 | 2,655 | 2,062 | 1.49% | 1,810 | 1 | CDP |
| Wayne | 39 | 2,223 | 2,280 | -0.49% | 388 | 6 | Village |
| Chicago | 40 | 0 | 0 | 0.00 | 3 | City |
Aurora is the largest city in DuPage County, with a population of 175,795.
Chicago is the smallest city in DuPage County, with a population of 0.
There are 40 cities in DuPage County, Illinois.